I now got the same issue. I tried to resolve it by reinstalling and it worked again for about two days. Now it happened again on startup. I tried the solutions that are suggested (change proxy settings, use a VPN, disable firewall, reinstall). None worked. After reinstalling it is even worse now as I get an error message while trying to finish installing it when opening the shortcut to the .exe. It tries looking for updates and then gives a popup with the "Oops! Something went wrong..." message. On my phone, in the same network on the same router it works just fine. It is honestly kind of frustrating to see that this error is coming up for different users for 3 years now and it still happens to players but isn't getting fixed.

Experiencing this now, and sucks even more because it's on arena open day 2 and decathlon finals day even though I was able to play just fine the day before.

I have tried reinstalling, logging in from mobile, tried changing network to 4g and all didn't work.

Hi everyone. I had this issue for a very long time and came back here to say how I fixed it.

In short, switching away from a wifi USB dongle to a PCI network card (Im on desktop) made the issue disappear.

I don't think there was anything wrong with the dongle - MTGA was the only application I had installed that had issues, and I use plenty of stuff with downloaders etc (think Steam, Adobe Cloud, etc.) But I suppose there was a compatibility problem between the dongle and the MTGA engine.

Anyway I hope this helps some of yous, and I hope some techie working at Wizards reads this so they can track the issue/bug down and try to make it so that people using wifi usb dongles can also play MTGA on their device!...

I am getting this as well. 4 hours straight today not able to login. Skipping Arena today as no time left to do any daily upkeep.

I noticed that the bug started after I won a traditional historic play, but an error pop-up appeared telling me that the game failed to give me the earned gold and xps.
I reinstalled the app twice (I play on Android) but the problem appears in 24 hours again.

Still have this bug. On PC, tried everything I could find online. I've stopped playing the game because of that... how ridiculous

@Mirrix16. I have never played on Mobile (yet) and am getting the same issue. I just started seeing this issue randomly yesterday 7/24. Uninstalling and reinstalling in Epic Games client fixed it. But today it's failing again. I will say it has been failing to close as of late for some reason. And I have to force it to close either with task manager or the windows crash handler thing.

I hadn't had any issues until yesterday (7/21) when I received this issue. I uninstalled and reinstalled Arena and it worked fine all day. Then today (7/22) I get the issue again. Arena loaded without an issue on my phone just now.

I am going to try to uninstall/reinstall again to see if that fixes it, but hopefully this can get corrected soon.

UPDATE: just finished a fresh install and it seems to work fine. i wonder if there is either an issue shutting down that corrupts a file OR if playing on mobile does something on the server side as each night i play on my phone in bed. Either way, hopefully there is a quick fix soon.

July 20, 2022: bug still exists. My internet and connection are fine, I have uninstalled and reinstalled MTG Arena four times and I'm still getting this message. I was playing on MTG Arena just fine last night - less than 24 hours ago!

this has been happening for the past week now. so many people below also have this problem and can't play the game. hope there is a fix or acknowledgement of this soon.

im having trouble with this how do i fix it?

While trying to connect getting the message: "Error Updating Data".
Other accounts do work, So It seems there's a problem with my account.

Anyone find a solution to this problem? I’m on a iOS tablet and getting the same problem. No problem with my internet

Posting my screenshot, because it looks different than OP's - assuming it is because OP posted this a couple of years ago.

I have had this error for about a week straight (as of March 24 2022) on my Windows desktop. No issue connecting via Android phone using the same wifi connection, so definitely not my internet connection.
Note: the arena server page is not reporting any outages, which would have explained this error

PC user here and I have tried all the troubleshooting solutions available online with the same "Error Updating Data - Please check your connection and try again" notification every time the game is launched.

Also tried playing via Epic Game platform; same result.

Same problem here. Since neo update i'm not able to run the game on Android Smartphone (HUAWEI P30).

me too

Does someone solve this issue? I had the same, i tried all procedures but i can't fix it... my connection works naturally...

Same here, I can log in with my friends account, but I can't get into the main menu with my own account. It stucks at the loading screen and shows this message. There is nothing I can do to fix that because the game literally works, my account is corrupted from the game side.