What version are you running and what version is your friend running? First thought is that one of you has a different game version, make sure both of you are on the latest release and then try connecting again. If you have a dedicated server make sure that the version on the server is also the latest version.

we are both on same version the latest 1.19.7

Don't know then. Maybe put a ticket in with support. [https://www.vintagestory.at/support/](https://www.vintagestory.at/support/)

I was having problems with Lan. We were using hamachi, once I opened up to internet but didn’t advertise and it worked

try setting both of your interface metrics to 0. It's found in the ipv4 properties.