We are unable to complete your call announcement 904

[ProDSouN]

Trying to call from US to Czech republic and getting :
"We are unable to complete your call announcement 904, contact Visible Support "

what does 904 means? what should I do?

I am using Visible+ plan on iPhone 13mini. 

[Aus101994]

I'm having the same problem. Crazy I saw your comment about this and its the only thing I've found about 904 anywhere really.