How to fix: Intermittent IMAP “BYE Temporary problem, please try again later” messages (courier-imap)
This problem has been bugging the life out of me ever since it appeared about a month ago.
Some background: I have a VPS with EUKHost.com that I have all my sites on. I have about 5 email accounts spread over my various domains on this VPS. I prefer to use IMAP, and have MS Outlook open for most of the day with it doing an automatic send/receive every 10 minutes or so. This worked great for 10 or 11 months.
As I said, a month ago this “BYE Temporary problem, please try again later” message kept appearing. What made it even more annoying is that Outlook displays it in a foreground message window that disturbs any application you may be using at the time the error occurs. Oh, and it also keeps the mail accounts “offline” until you do a manual send-receive. E-X-T-R-E-M-E-L-Y annoying when this happens every few minutes. I ended up closing Outlook for most of the day because it just bugged me so much.
EUKHost couldn’t fix it. Various google searches I tried before didn’t help. Today, I finally have some free time to sit down and finally figure this one out.
First, I had to confirm that it was a server problem and not a problem with my Outlook. Because this is an intermittent problem, this was difficult to do and partly the reason why it took me 4 weeks to do something about it. After some research, I found out how to debug courier authentication errors. I wasn’t 100% sure this was where my problem lay, but as I had nothing else to go on, I decided to give it a try.
How to debug courier authentication errors:
- Edit
authdaemonrc(I found mine at /etc/authlib/authdaemonrc) - Set
DEBUG_LOGIN=1 - Restart
authdaemond:
# authdaemond stop
# authdaemond start - At this point, all debugging output goes to syslog at level ‘debug’, which is normally not shown. You will probably need to change your /etc/syslog.conf file to be able to see these messages. Add this line to the end of /etc/syslog.conf:
*.debug /var/log/debug - Create the log file and restart syslog:
# touch /var/log/debug
# killall -1 syslogd - Keep an eye on the log file:
# tail -f /var/log/debug
OK, so now we’re debugging authentication errors. I opened Outlook and just continued doing whatever I normally do until the error message appeared. It wasn’t more than 5 minutes before it appeared. In the log file I saw this:
...
Feb 14 15:57:34 vps authdaemond: authpipe: TEMPFAIL - no more modules will be tried
...
Feb 14 15:57:34 vps imapd: LOGIN FAILED, user=paul+fuc.it, ip=[::ffff:222.144.254.98]
Feb 14 15:57:34 vps imapd: authentication error: Input/output error
This confirmed that it was indeed an authentication problem. The input/output error confused me for a while – was it a hardware problem? After researching more, I found this useful bit of text within the authdaemonrc.dist file (yes, the configuration file I was editing before didn’t have any comments…)
##NAME: daemons:0
#
# The number of daemon processes that are started. authdaemon is typically
# installed where authentication modules are relatively expensive: such
# as authldap, or authmysql, so it's better to have a number of them running.
# PLEASE NOTE: Some platforms may experience a problem if there's more than
# one daemon. Specifically, SystemV derived platforms that use TLI with
# socket emulation. I'm suspicious of TLI's ability to handle multiple
# processes accepting connections on the same filesystem domain socket.
#
# You may need to increase daemons if as your system load increases. Symptoms
# include sporadic authentication failures. If you start getting
# authentication failures, increase daemons. However, the default of 5
# SHOULD be sufficient. Bumping up daemon count is only a short-term
# solution. The permanent solution is to add more resources: RAM, faster
# disks, faster CPUs...
I underlined the important bits. Sporadic authentication failures? Check. Default of 5? Uhm…. mine’s set at 2. So, I upped it to 5, restarted authdaemond and waited for Outlook. It’s been going for a few hours now and no errors. I hope this resolves it finally. I also hope that this helps someone else and prevents someone from getting as fed up with it as I did. Leave a comment if it helped you!