I am fairly sure that only if the system disk is full there will be problems logging in. How full the other disks are shouldn't matter, at least not for logging in. But if you can move some files around and free up some space on all disks it wouldn't hurt.
good morning and thank you very much for pointing me to the solution.
I turned off all the HDDs from the power supply, I only left the SSD with OMV4 active.
it didn't let me connect to the WebGUI even with all HDDs disconnected.
So I used the USB key with the software to partition the HDDs, from there I found that the SDD had 20GB occupied for the whole. I had left 35GB unallocated.
So I made a whole 55GB partition.
I rebooted and everything started working.
question: why the 8GB of OMV4 became 20GB?
I never put any FILES on this SSD.
Does OMV4 create temporary files and overload the space where it is installed?