no matter what server I try to join, it will not let me join any server, all it says is this: Handshake failure: invalid key for user, is there any fix for this?

Go to KSP folder\GameData\DarkMultiPlayer\Plugins\Data and delete the privatekey.txt and publickey.txt files. It should work.

thank you, I will try that now

the files keep reappearing in the folder when I boot the game back up, odd, any fix for this please?

(Where is the 🤦 emoticon when you need it?)
Yes, a new set of keys are made when you delete them. Just connect to a server and everything should be fine.

i keep deleting them and yet, it still says I cannot connect, this is flip the table levels of frustration currently.

You only have to delete them once. You don't need to keep deleting them after you did the first time.
Be sure that your mod is up to date, it could be what's causing the issue,

yeah seems like a different issue. Would the logs be able to help with this?

@RockyTV deleting the keys will cause this problem, you're supposed to delete DMPServer/Universe/Players/playername.txt :)

Luckily DMP backs up their keys in KSP/saves/DarkMultiPlayer :P

Invalid key just means you've wiped your install without copying over the DMP save, or the DMP plugin - it is indeed this issue.

I am in 1.2.1 with DMP 1.2.1 I followed the coneseil give give but I still can not connect (server: Nuts - Mod Friendly Server) but this does not work on any server and I do not know what to do. Surprising its progress in 1.1.3 but not in 1.2.1. WHY ?? : /

Ask the server admin to remove your key file from the server's universe.

Ask the server admin to remove your key file from the server's universe.

This did it, thanks, i actually kept my science. Didnt expect that.