I have many clients connected to my wlans, but this client (It's a wallbox) refuses to keep its IP address and disconnects

E8:FD:F8:0B:B0:78@wlan4: disconnected, received deauth: sending station leaving (3), signal strength -87
E8:FD:F8:0B:B0:78@wlan4: connected, signal strength -86
defconf deassigned 192.168.88.3 for E8:FD:F8:0B:B0:78 HF-LPT230

I haven't done any complicated configuration to the router, but few days ago i set up queues and updated to 7.9.1. can it be related? Other clients works just fine.
Any help?

Update: For some reason the update to the 7.9 changed my security profile dedicated to the wallbox from tkip that was previously to aes and tkip both. So it is resolved.

Mmm...tkip is old, you shouldn't use it.
Besides, looks like signal is a bit weak (-87). You might (still) have a problem there.