This is applicable only to Teracube One users. Teracube 2e users are not affected by this.
Update (July 29, 2021): Great news - we have an initial notification from AT&T that Teracube One will be approved on their network (including Cricket) by mid-next week (Aug 4-5). At that time, all you will have to do is put your SIM in a different phone and then bring it back.
We have a very important update for Teracube One owners that use Cricket Wireless or AT&T networks in the US. AT&T has said that they will be shutting down their 3G network in 1 year from now (Feb 2022) and they have stopped activating new phones which do not support their HD calling. As of now, Teracube One phones are working fine since they were activated before.
If you own a Teracube One please do not update or remove your SIM card .If you follow these rules your phone should continue to operate as normal while we follow up with AT&T. Read this community discussion for more details