tunnel no longer established :: how to debug?

[Adrian Sevcenco]

Hi! After a change of connection point (the same ISP but different location, but with the same wireless, and end-points)
the tunnel no longer is established. Nothing in the wg configuration is changed ...
from the "client" machine to the "server" end-point i can do:
root at hal: ~ # nc -u -vz sev.HHHHHH 43333
Ncat: Version 7.80 ( https://nmap.org/ncat )
Ncat: Connected to HHH.HHH.HHH.HHH:43333.
Ncat: UDP packet sent successfully
Ncat: 1 bytes sent, 0 bytes received in 2.01 seconds.

How can i debug further to see why the connection is not established?
Thanks a lot!
Adrian