@widge7: Are you connected to a secure Wi-Fi network, and attempting to update via Settings > Software update > Download and install? If so, and if no updates are available, then you may wish to try using Smart Switch on your home computer to see if you're able to update in this manner.
To begin with, please follow the link below, and click on 'How Do I Get Smart Switch On My PC or Mac' to download the relevant version
https://www.samsung.com/uk/support/mobile-devices/how-do-i-backup-my-smartphone-to-my-pc-or-mac/
Once installed, open Smart Switch, connect your S21 Ultra using the USB cable that came packaged with the device, and look for an update prompt on the landing page, next to your device details.
I am having the same issue with my S21+ (oddly my husbands too, same model). I have contacted AT&T and Samsung and finally gave up. I have tried Smart Switch and the Settings > software update -- neither worked. These phones were purchased in installments on our ATT bill back in APR of 21. Any help would be help, I have been googling this for almost a year now.
![Screenshot_20221208-121639_Settings[4293].jpg](https://eu.community.samsung.com/t5/image/serverpage/image-id/1436636iA20DEF777E1B6F27/image-size/large/strip-exif-metadata/true?v=v2&px=999 "Screenshot_20221208-121639_Settings[4293].jpg")
![Screenshot_20221208-121646_Settings[4294].jpg](https://eu.community.samsung.com/t5/image/serverpage/image-id/1436635iB8F1CB45688426EC/image-size/large/strip-exif-metadata/true?v=v2&px=999 "Screenshot_20221208-121646_Settings[4294].jpg")
@texasMadeQueen: Where did you purchase your Galaxy S21+ from? If the phone was intended for use outside your current country, then this can lead to compatibility issues due to software variances that exist in our devices from region to region. I can see that your Google Play system updates aren't going through either, which does suggest to me that the phone(s) are not intended for use in the US.
