Sdl Trados 2017 network license activate/deactivate problems

good afternoon,
We have been working for 4 months with 4 licenses of sdl trados 2017 in network mode. We have 4 different computers pointing to that license with the license server installed on a virtual machine.

So far we have worked without problems. Now, however, every time one of the computers opens Trados, it says "There are no more licenses available on this server".

Instead, if I go to the license server, I deactivate the license and re-enable it, the computer can open trados without problems. This operation I have to do every time one of the 4 computers opens Trados It happen from last week.

What can i do?

 

Thank you.

Regards.