Exactly same problem . My cameras (21- v2/v3 ) are in Serbia too, two years already. .All of them two weeks ago went offline .
Login is now possible only if using VPN (doesn’t matter US or Europe server) but even with VPN is not possible to setup cam again (timeout or cam can’t recognize QR code) . Without VPN always wrong password or user name error. Still even with VPN all cam’s are offline.
I have all together around 50 cameras (yes i know its a lot 
but is a big property ) , all other cam’s(Blink,Inqmega…) ,Alexa , other wifi devices working normally, Only problem with Wyze!
Also Eero app shows up/down activity for all offline cameras , they upload /download every day …
Ticket( 2343884)) opened 10 days ago and still no solution from Wyze support