Game Crashing when friend joins in COOP

My game keeps on crashing everytime my friend tries to connect to my farm. Started after update to 1.4. I've read about this problem a few times but I could never find a fix. Both on Win10. We never had a problem before that.

 

Can you both go through this list please?


Common troubleshooting steps:
1. Check that SDV is up to date and your save is loaded in co-op mode.
2. Make sure you have enough cabins built for the number of players.
3. Make sure the server is set to online in the game options.
4. Turn firewalls and antivirus off for all players.
5. Make sure everyone is logged onto Steam/GoG Galaxy.
6. Do a content reset on Steam/GoG for all players: https://stardewvalleywiki.com/Modding:Player_Guide/Troubleshooting#Reset_your_content_files
7. Restart all player's PCs.
8. Restart all player's routers, and check for any updates for your router. https://www.wikihow.com/Update-Router-Firmware
9. Try reinstalling .NET Framework 4.5.2 and XNA Framework 4.0 (see https://stardewvalleywiki.com/Moddi...ting#Nothing_happens_when_you_launch_the_game for links).

 

We fixed it, thanks a lot! It may have been the invite-type or the router reset we did a few times over the holidays. Whatever it was works now, so thank you