No authentification on Linux

[Rafael]

Hello,
I have Veyon installed on 2 Windows and 1 Linux. One of the windows is my master and I have imported the config file and the public key into the 2 other. I have no problem with the Windows one, but I can't connect the Linux one, it say "authentication failed or access denied" with a padlock icon.
I thought it was a problem with the groups on the key, but the error stays the same no matter the group I put the key in, so it must be something else. what else could it be ?

Thanks