Hello Swild (Sebastian)!
Our apologies that this reply is coming so late, please note others have posted on the same issue within the Zoom Community and there is a URL below.
By default you are allowed per-user-account: One active Computer, one Tablet, and one Mobile device in use at any given time--logging on on computer 2 will log out computer 1 in your scenario, and this is by design.
The most direct route may be to get a 2nd account, or contact Zoom Sales to see whether alternative options may be available for your account. https://explore.zoom.us/en/contactsales/
Here is our support article: https://support.zoom.us/hc/en-us/articles/360000787483-Can-I-use-Zoom-on-multiple-devices-
The most likely answer has also been posted in the community here: https://community.zoom.com/t5/Meetings/Zoom-keeps-logging-me-out/m-p/9717/highlight/true
Apologies again for the late reply. Please let us know if this helps resolve the issue by marking as a solution.
Thanks for Zooming!
Delivering Happiness!