Disconnected from server issue

My friend and I constantly get disconnected from the server messages when playing co-op regardless of who is hosting. we have tried various invite methods such as through steam, invite code, join game, etc. and all result in at least daily (in game) disconnections up to 3 disconnects an in game day. The guest is always the player who gets disconnected from the server. This happens at random times including but not limited to: loading from one zone to another, cutting trees down on our farm, fishing, walking across a zone (from market to black smith), fighting in mines, mining, etc. We have restarted our computers, verified the integrity of files on steam, uninstalled and reinstalled, and attempted to use LAN through Hamachi - all of which have failed. Please provide any guidance!
When disconnected and reconnected the guest does have the same inventory they did just before disconnected and spawn in their house on the farm.
We are also now having an issue where the guest gets disconnected each night when the game goes through a summary screening and the host gets stuck on "waiting for other players". This is where we have to both close our games and restart.

 

Just a basic question, do you have Windows Firewall on? It cause a lot of issues with games.

 

I did at first but we both turned it off and had the same issues. But thanks for the attempt.
We also did a ping test and found that there is no correlation between the disconnects and lost packets. Even with no lost packets, the disconnections regularly occured.

 

You or your friend uses mods? Some mods have issues with multiplayer.

 

No mods on either side. We knew that may be an issue and so we have just the original game through steam.