I was curious and asked this question in a tech ticket and here's the response-
Generally speaking, connection issues can never be ruled out on the internet, so there is no such thing as a guarantee against lags and kicks. However, there are some precautions your friend can take:
- Check their network preferences to ensure that the connection is set up correctly.
- Keep in mind that additional traffic can temporarily slow down the connection, so don't download data while playing.
- Contact their internet provider and ask them to check their routing if they keep having problems when connecting to Tibia.
- As a last resort they may consider logging into the game using a different provider.
I see this information and additional information can be found in FAQ: Kicks
If your still having issues please Create a ticket to see if Tibia can help further. I hope some of this helped and that it's an easy fix.
I know in the past my friends and I were all playing on computers at the same time and we would randomly get kicked from the game. Never would anyone get kicked out if it was just 2 of us online. But when it was 3 of us we would get random kicks. I reported it to Tibia but not sure what was going on.