Roundcube, POP3, IMAP Unable to Connect (out of memory) Print

If you’re unable to connect to Roundcube, POP3, or IMAP, the first step is to make sure Dovecot is running by using the following command:

systemctl status dovecot

If it shows it as active (running) then dovecot is running and the service is started and that is not the issue.

Jan 12 21:28:52 servername dovecot[19306]: imap-login: Fatal: Failed to read config: mmap(/var/run/dovecot/config) failed: Cannot allocate memory
Jan 12 21:31:01 dal217 dovecot[19306]: pop3-login: Fatal: master: service(pop3-login): child 19312 returned error 83 (Out of memory (service pop3-login { vsz_limit=128 MB }, you may need to increase it) - set CORE_OUTOFMEM=1 environment to get core dump)
Jan 12 21:28:52 servername dovecot[19306]: managesieve-login: Fatal: master: service(managesieve-login): child 19317 returned error 83 (Out of memory (service managesieve-login { vsz_limit=128 MB }, you may need to increase it) - set CORE_OUTOFMEM=1 environment to get core dump)

If you encounter any errors related to 'out of memory' with pop3-login, imap-login, or managesieve-login, it means the default memory limit of 128MB for Dovecot login processes is too low on your server. You can correct this by increasing the Process Memory Limit for Authentication (MB). We suggest increasing Process Memory Limit for Authentication (MB) to 256 which you can do from WHM on the "Mailserver Configuration" or by modifying /var/cpanel/conf/dovecot/main and changing the login_process_size from 128 to 256.