Beard's post in Internet Usage? was marked as the answer
It would likely be connection / router related. If you are playing on a wife I would recommend using an ethernet connection instead.
Other than that, as you mentioned it could be a router issue, if you have any security such as a firewall enabled on the router it may affect the connection. There isn't anything specific I can suggest to fix it though as internet issues are extremely dependent on the location, hardware and the internet setup you have.
Beard's post in Got this screen whenever I boot the game with debug enabled. Any fix of this? was marked as the answer
Generally this is caused by enabling debug mode + mods, try going to "C:\Users\YourUserName\Zomboid" and delete the "mods" folder there and see if you can launch the game then?
Beard's post in Was just gifted the game and when I try to open the game, it does not start. was marked as the answer
Thanks, seems like this would be the issue:
You seem to have the game in a path with several special characters which are !!!!
The game cannot read those characters properly, meaning either move the game to a different folder or remove the characters from that path.