Users may be unable to login with this message:
20XXXXXX 00:00:12.345 [essential] [ERROR] WSS_acceptor, port 7500: [2021-05-23_11:48:55.209] Uncaught Exception in Thread[WSS_acceptor, port 7300,5,WORKSTATION_SVR]
java.lang.OutOfMemoryError: Java heap space
Release : 12.2
The JRE is not able to acquire adequate memory
Increase memory on host/server. Users may also decrease the memory if DE server is using less memory than total allocated.
See this KD on how to change JAVA HEAP in dSeries (DE).