Hi Maximilian Meissner,
There could be three reason for this error.
1. For your system the port 5050 is to enabled or to troubleshoot as I see the server is in port 5050.
Corrective Action: Pl take the confirmation from SAP HANA administrators and take to forward to your computer administrator. This is a common issue. When we are first time access the HANA server. We have to make our computer (Desktop/Laptop) enabled with the new PORT.
Solution: Your computer should be enabled to communicate to server thru port 5050.
2. Your account is created recently and your profile is not yet reflected in the hana system.
Corrective Action: Pl take your administrators help.
3. At that time Server is busy/unavailable to honour your request.
Thanks&Best Wishes -Ashok