Resolving apparent login failures with SMTP and POP
Following upgrades or initial installations, you may find that your mail client is unable to connect successfully to your SMTP submission port or to the POP3 port. Some mail clients will report this as a password error; others may simply report a generic problem.
One possibility is that the 'vchkpw' daemon does not have enough memory to run. You can test this by hand-simulating a POP session with, for example:
telnet yourhost.com pop3
Connected to yourhost.com.
Escape character is '^]'.
(user input is shown in bold).
The server should respond at this point with '+OK'. If it responds:
/home/vpopmail/bin/vchkpw: error while loading shared libraries: libresolv.so.2: failed to map segment from shared object: Cannot allocate memory -ERR authorization failed
you have probably encountered a memory problem. To resolve this, do:
Step through the files one by one, checking each one for a line that resembles:
/usr/bin/softlimit -m 48000000
In each such file, change the '48000000' to '64000000'. Then restart qmail with:
qmailctl stop qmailctl start
and try your POP session again. If it now succeeds, the problem is probably resolved. If not, try raising the limit again.