Cannot switch, ssh to specific user: su: cannot set user id: Resource temporarily unavailable?
It could be possible that the max user processes (-u) 1024 is too low.
Remember that processes and threads are counting together.
You can use ps -eLF | grep adtech | wc -l to show your current value.
Look in the jvm log for evidence it is hitting resource limits. Stack size might be the problem, depending how many java threads the killed process was running.
Searching on your error message finds bug reports for pam_keyinit: check with your vendor's repository whether an updated version is available.