This isn't a you issue...

Hello Antaresss.
Such error can occur when:

• Your computer is too slow to handle the processing in time
• Your Internet is too slow to send the data in time
• The server is too slow to process the recieved data in time

Or mix of all of the above.
Regards,
Geez

Ok... so... Geez, What tests can I do to prove to you whether this error is local or not?

test internet connection and speed
try a different network (If possible, connect PC to a different internet connection (such as a mobile hotspot or another WiFi) and try joining server. If you don’t get the error, your home network might be the issue)
try wired connection (If you’re using WiFi, try connecting via Ethernet to rule out wireless issues)

https://www.reddit.com/r/dayz/comments/1g7tcfv/authplayerloginstate_fix/ possible suggestions from another user with the same issue

My connection is wired and extremely stable because I do livestreams and stuff like that.
I've already read this topic on Reddit, and changing the nickname does work, but shouldn't it be some error in the game itself? Is there a possibility that I can send you some LOGS for analysis and check what exactly is happening, perhaps?

In T191992#2810074, @Antaresss wrote:

My connection is wired and extremely stable because I do livestreams and stuff like that.
I've already read this topic on Reddit, and changing the nickname does work, but shouldn't it be some error in the game itself? Is there a possibility that I can send you some LOGS for analysis and check what exactly is happening, perhaps?

Can you try to connect to an official server, and if it kicks you out with the error message, can you provide the following?:
Steam ID (nickname)
Server ID
Approx. time

Sure, I can do that and I will send you all the information you requested.

In T191992#2810023, @Geez wrote:

Hello Antaresss.
Such error can occur when:

• Your computer is too slow to handle the processing in time
• Your Internet is too slow to send the data in time
• The server is too slow to process the recieved data in time Or mix of all of the above. Regards, Geez

This is not true, EVERYONE gets this error over the past year or longer, this issue got worse around 1.24 and there are multiple tickets on this

A lot of players need to connect multiple times to join a server.