Zerotier dont work

Dear friend,

I added my teltonika RUT240 to my zerotier network. It came automaticaly, I autorised. I have followed your youtube video to create all this. Im using firmwere 7.6.19. All worked fine since over one year, and suddenly stoped. I created all the same as last time, but unfortunately without success. I woul appreciate your help.

Best regards

Perica