That may also indicate AllowedIP issue, if I'm not mistaken?
Yes, that seems like a wireguard issue. Perhaps wireguard has problems with multicast dst because it does not know which key to use? Just guessing, i do not know wireguard.
Possible workaround would be to configure OSPF on that iface as ptmp and specify neighbor address using 'neighbors' option. In such setting only unicast is used.
Since the 0.0.0.0/0 approach didn't work, I'll try this next and see what happens. Thanks for suggesting alternatives.
Although unrelated, i would suggest to remove these OSPF options;
tick 2; rfc1583compat yes;
Care to elaborate why? I do trust that you will know better.
'tick 2' will increase convergence time form ~1 sec to ~2 sec.
'rfc1583compat' is an obscure OSPF option for compatibility with ancient RFC 1583 in some multi-area setups for the price of persistent routing loops in some other multi-area setups. Completely irrelevant for single-area setups.
check. thanks for clearing that up.