First reported to Google Fi on 15 Oct 2020, mine failed on 16 October 2020. After waiting 2 1/2 days for Google to find a fix, this is what I found that works:
Steps were:
1. Download previous version of SIM manager, SIM Manager D.1.8.328598780-google from https://www.apkmirror.com/apk/google-inc/esim-manager/, and install over current version.
2. Attempt to activate using that version, failed with error E0X3002716
3. From Google Play, upgrade to latest version of SIM manager...
Read more
Steps were:
1. Download previous version of SIM manager, SIM Manager D.1.8.328598780-google from https://www.apkmirror.com/apk/google-inc/esim-manager/, and install over current version.
2. Attempt to activate using that version, failed with error E0X3002716
3. From Google Play, upgrade to latest version of SIM manager...
Read more
