“RO5 – Invalid SIM” error on Galaxy S6, more connectivity issues

S6 Edge

Our post for today discusses internet and connectivity issues on #GalaxyS6. We look forward to helping our Android community via this post.

These are the topics for this article:

  1. “RO5 – Invalid SIM” error on Galaxy S6
  2. Galaxy S6 keeps getting disconnected from PC
  3. Telekom Romania Galaxy S6 not detecting 4G LTE network
  4. Download status bar on Galaxy S6 stock browser gone
  5. Galaxy S6 hotspot not working in Israel
  6. Galaxy S6 not receiving notifications from apps when in school Wi-Fi

If you are looking for solutions to your own #Android issue, you can contact us by using the link provided at the bottom of this page.


Problem #1: “RO5 – Invalid SIM” error on Galaxy S6

Due to national T-Mobile Data breach with Experian I recently closed my account with T-Mobile and ported over to AT&T. Of course I called to request an unlock for my Samsung Galaxy S6 prior to porting which apparently went through without a problem.

After porting over and AT&T activated my phone line I checked out calling, texting, and internet services which all seem to be working just fine. This morning I was checking out my e-mail (coming in fine) and noticed a red Wi-Fi symbol at the top of my screen I had not seen before.

It was then I saw the error message (ERO5 – Invalid Sim). Something about the Wi-Fi service is still T-Mobile and isn’t working but I cannot seem to locate exactly what it is that isn’t working. I am connected to my home network now

(5g) without any problems. Again, all connections seem to be working.

My concern is that just when I need it most the problem may become very apparent which seems to be the case when dealing with any electronic device! LOL.

Please Advise.

Thank you for your generosity and willingness to help others! Sincerely. — Max

Solution: Hi Max. The ERO5 – Invalid SIM error is a T-Mobile code and appears to be related with their Wi-Fi Calling service. We don’t work for T-Mobile so we are not 100% sure if the phone’s Wi-Fi calling feature still requires a specific T-Mobile SIM card (with label TM9177) for this to work when you’re on AT&T network. Try to call T-Mobile and see if they can give you a workaround.

Keep in mind that your phone may have been carrier unlocked (which means you can now use any other SIM card from other operators), but the firmware is still T-Mobile. Some services and features on the phone may still require a T-Mobile SIM card to work.

Try working with AT&T technical support team and ask them if there’s a way for you to use Wi-Fi calling (as it appears that’s the trigger for the error) on their network.

Problem #2: Galaxy S6 keeps getting disconnected from PC

I’m unable to connect my phone to my computer. I’ve used different USB cables, tried all of the various ports (after making sure they work by plugging in other USB things, like my portable hard drive), I’ve downloaded the drivers, I’ve downloaded Smart Switch, I’ve spoken to multiple Samsung Agents and they had me try a multitude of things, none of which worked.

I was forced to do a factory reset recently, so I’ve even tried that, and it still won’t work. It just repeatedly connects and disconnects, over and over again, driving me insane with the constant binging noise it makes. I’ve had this phone for a year and I’ve been trying different things since I got it. Once the stupid thing decides to connect, I need to stay still as a statue for however long it takes to sync whatever I’m syncing, because if I move an inch, it starts the whole process over again. Getting really, really frustrated. The last agent I spoke to says it’s related to my computer, but everything else works just fine. — Nicole

Solution: Hi Nicole. Please try to connect your phone to another known working computer. This is verify if the issue is due to a fault in your phone (probably a malfunctioning microUSB port), or if the current computer you have has some compatibility issues. There’s really nothing much that you can do about this issue right now other than this.

If your phone connects to another computer just fine, troubleshoot your computer. If it’s the other way around, have your S6 replaced.

Problem #3: Telekom Romania Galaxy S6 not detecting 4G LTE network

Hello. It’s not usually my thing to send SOS mails, but I really need help with my Samsung GALAXY S6 EDGE. Firstly, nor my subscriber nor a GSM service couldn’t tell what’s the trouble:

I have recently made a new subscribe to Telekom Romania for a business plan that include a 4G net speed. The problem is that I have internet on my phone but is not working at 4G speed. Instead it is writing just a H+ and two arrows in the left of the signal levels.

I called the operator. They just resend me the standard configuration settings that should be installed. I did install them and restarted the device but still the same. They also told me that 4G speed is active on my subscribe.

After that, I called a friend that owns a GSM service store and he is a pro, but he also didn’t know how to solve the problem.

So, I have found your website, and I hope I will get a favorable answer.

Please note that this phone was blocked on Vodafone Romania, but I unblocked it by the IMEI code at my friend’s GSM service to work with Telekom RO.

He said it will have no problem, and I think so because when I had the other SIM without having the phone unblocked and with another number on Vodafone on this device it also appeared H+. I also have a friend that has the same phone and when we go to the same locations he has 4G and I don’t – his phone shows the 4G sign and mine the H+, so it’s not a matter of covering… Thank you ! If you will solve my problem, you are true professionals and I will spread the word in my country about you. — Petrof

Solution: Hi Petrof. In order for your Galaxy S6 to connect to your operator’s 4G LTE network, it must be configured properly first. Call Telekom Romania and ask them to help you configure your phone’s APN settings. It should work.

Of course we assume that your S6 model is LTE capable. This means that your S6 must have the necessary hardware chip to be able to work.

If your phone is fully LTE capable, make sure that LTE is enabled by going under Settings>More Networks>Mobile Networks>Network Mode. Choose GSM/HSPA/LTE (Auto Connect).

Problem #4: Download status bar on Galaxy S6 stock browser gone

Hello there. I bought a new Samsung Galaxy S6 Edge last month which is working perfectly fine. Recently I was downloading a file from the default Android web browser (Internet). During the process I just disabled the download status bar of the browser  accidentally. Now the content gets downloaded but the downloading status bar does not appear. I am not able to find the option where the same can be enable. Please help me in this regard.

Regards. — Pankaj

Solution: Hi Pankaj. Try to clear the app’s data to “re-install” it. This will bring all default app settings back. Here’s how to do it:

  • Go to Settings.
  • Proceed to Applications.
  • Select Manage Applications.
  • Tap the All tab.
  • Look for the browser app and tap it
  • From there, you will see the Clear Data button.

Problem #5: Galaxy S6 hotspot not working in Israel

Hi. Maybe you can help me. I have a friend who has from AT&T an unlocked Galaxy S6. In the USA he can make his device in to a Hotspot and use his AT&T service. In Israel using a carrier there called 012 Mobile (they use Orange Network in Israel) when he goes to activate the Hotspot setting it slips back. The basic message it says “Incorrect SIM or service unavailable”.

I know that this carrier doesn’t restrict tethering as others have been successful in using their smartphone and this carrier for a hotspot but this is not the first person who has had an issue with tethering.

By the way I don’t have access to this guy’s device at this time and he is traveling so I do not know what version software he is using or what apps he recently installed.

I would appreciate getting your take on this. Thank You. — Nat

Solution: Hi Nat. Hotspot feature is sometimes locked by an operator (at firmware level) so it only works on their network. Some carriers put hotspot restrictions on the account (as a value-added service). If your friend is positive that his or her Israeli carrier allows hotspot feature on the account level, then the reason why it’s not working may be due to firmware limitation set by AT&T. To circumvent this limitation, he must root his phone. If he is amenable to rooting, ask him to use Google to find online resources on how to do it.

Problem #6: Galaxy S6 not receiving notifications from apps when in school Wi-Fi

I am using my college Wi-Fi and for the first month it worked perfectly fine. Now when I use it, my phone doesn’t bring up notifications until I open into the app and realize i have a message/notification. It usually happens with social media apps like Groupme, SnapChat, YikYak, and a few others. It works for Facebook, and Chrome and everything else works fine.

I also realized that all apps and notifications work on 4G and other Wi-Fis besides my college Wi-Fi. My college Wi-Fi perfectly works when i put my phone in airplane mode and turn on Wi-Fi and the tech support at school really has no idea what’s wrong even after they went through my settings to see if anything was blocking the connection.

I can’t tell if it’s my phone or my schools Wi-Fi at this point. If you could help me out that would be highly appreciated. — Michael

Solution: Hi Michael. Please do the basic software troubleshooting on your phone to see if it’s device issue, or a Wi-Fi network problem.

Try wiping the system cache first.

  • Turn off the device.
  • Press and hold the following three buttons at the same time: Volume Up key, Home key, and Power key.
  • When the phone vibrates, release the Power key but continue to press and hold the Volume Up key and the Home key.
  • When the Android System Recovery screen appears, release the Volume Up and Home keys.
  • Press the Volume Down key to highlight ‘wipe cache partition.’
  • Press the Power key to select.
  • When the wipe cache partition is complete, ‘Reboot system now’ is highlighted.
  • Press the Power key to restart the device.

A factory reset may be effective in this case too.

  • From the Home screen, tap the Apps icon.
  • Find and tap the Settings icon.
  • Under the ‘Personal’ section, find and tap Backup and reset.
  • Tap Factory data reset.
  • Touch Reset device to proceed with the reset.
  • Depending on the security lock you used, enter the PIN or password.
  • Tap Continue.
  • Touch Delete all to confirm your action.


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If you are one of the users who encounters a problem with your device, let us know. We offer solutions for Android-related problems for free so if you have an issue with your Android device, simply fill in the short questionnaire in this link and we will try to publish our answers in the next posts. We cannot guarantee a quick response so if your issue is time sensitive, please find another way to resolve your problem. 

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One Reply to ““RO5 – Invalid SIM” error on Galaxy S6, more connectivity issues”

  1. I have an unlocked Sprint S6 Edge Plus that I am trying to hand down to my daughter since I have upgraded to the S8 Plus. I keep getting “Invalid Sim” when I enter the T-mobile sim card. When I enter the Sprint card that came with the phone, it picks up network and goes into hands-free activation mode. I can cancel out of that. My main issue is with the Sprint card, Under: Settings>Connections I have a Mobile Network option. I change to GSM/UMTS and run a scan, under Access Point Names and T-Mobile and AT&T show as options. I select T-Mobile and it tries to register. Due to the Sprint car (I’m assuming) it will not register. When I shut the device down and reboot with a T-mobile card, I get “Invalid Sim Card” When I go into settings with the T-Mobile card entered, the Mobile Network option is missing. I feel like there is a step I am missing but can’t find answers anywhere. Please help!

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