I use Sourcetree 3.4.2
For authentication I use OpenSSH.
I use different SSH keys for Github and Gitlab. If I go to Tools > Add SSH Key... and add both private keys one after the other, they are separated by semicolons in Tools > Options > General > SSH Key:
However, I cannot establish a connection to either Github or Gitlab with them!
If only the path to one key is entered there, authentication works.
The question now is whether the addition of several keys is the bug or the processing of several paths separated by semicolons.
At least both passphrases are requested to start Sourcetree.