Postfix blocks my PC

Hello Community!

today i upgraded my 20.04 installation to 22.04. At a point in the process, a config window for a mailserver popped up. i closed the window without doing a configuration. After the Upgrade was done, I rebooted my PC. After the Plymouth, my screen stays dark and the mousecursor flashes randomly.

somehow I triggered an appearing failure message: "Failed to start Postfix ma* Transport Agent (instance -)"

how can I fix this?

thank you in advance.