Wait so let me get this right, you blame the My Cloud for a problem caused by AT&T and their equipment?
It is a WELL KNOWN issue in this subforum that AT&T Uverse routers have problems with the My Cloud. The solution, until AT&T decides to fix their routers, is to use a switch or second router in between the My Cloud and the AT&T router.
If one had done a forum search they’d find several other threads of AT&T users having trouble because of the AT&T supplied router. Here are just three:
https://community.wd.com/t/cant-connect-my-cloud-using-att-uverse-1gig-fiber-service/140412
https://community.wd.com/t/changed-internet-providers-now-wd-my-cloud-does-not-connect/168186
https://community.wd.com/t/cant-connect-to-u-verse-help/150157
