This is commonly caused by running out of file descriptors.
There are different file descriptor limits.
There is the systems total file descriptor limit, what do you get from the command:
From this command you will get 3 numbers. First is the number of used file descriptor the second is the number of allocated but not used file descriptor and the last is the system max file descriptor. If either of the first two numbers are new otr at the third you need to increase the number of file descriptors for the system of find out what is consuming them.
Also, you can increase the value of "nproc" parameter for user or all user's in /etc/security/limits.d/90-nproc.conf