When there is already existing connection to one database on server, then attempting to connect to server sometimes stalls. Even when trying to connect databases, that do not exist. And when that happens, then original open connection also stalls.
I wrote powershell script to connect 36 databases (using ado.net database driver), of which only first exists. And I connected first database in Flamerobin and then executed the script. It successfully connected first database, failed to open next 5 (because those do not exist) and then attempting to connect next database stalled. And when I tried to disconnect Flamerobin from first database it stalled also.
Problem does not appear on Firebird 3.0.5