S21 will not register to AT&T network after switching from Sprint and unable to retrieve voicemail

[sexyNMbabe]

My phone originally came from Samsung with Sprint sim card. I've since switched to AT&T. Now, I can't check my voicemail cause all my stuff is still trying to register under sprint....I'm not with SPRINT ANYMORE!! I've reset my phone numerous times...I'm at my wits end! 

[userGz37MU98H6]

Yes, I have at&t and the samsung unlocked version. Just to google play store and download at&t visual voice mail and you will be good to go. I had to due that and use it now on my zflip 5g and my s21 ultra 5g .

[sexyNMbabe]

But the Samsung version of at&t. When I bought the phone, it was sprint.. I've since switched to at&t and now I can't check my voicemail cause it's all still on sprint.

[userGz37MU98H6]

See this app you will find in play store .look at my screen shot.

[sexyNMbabe]

I tried, couldn't find it

[Miavonnie9]

The logo sprint you are referring to may be incentive to that particular device

[sexyNMbabe]

So I can only use sprint? That is ridiculous 😳

[LongHiker · Accepted solution]

@sexyNMbabe the problem is probably caused by the Sprint SW loaded onto the phone. This has defaults which are probably overriding the manual changes that you make.

The solution is to flash the device with AT&T's SW. They probably will do this for you at an AT&T store. Make sure that you have everything backed up before that since it will erase the data and apps in the process. 

A workaround... Download the Google voice app and set it up. Then set your AT&T account so that call forwarding goes to the Google voice number. Now your voice mail will all end up in the Google voice app. 

[fungurl2010]

Ok calm down to check your voice-mail press and hold 1on your keypad on your phone to hear your voice mails

[sexyNMbabe]

I've done this. It dials and hangs up