I'm currently experiencing an intermittent problem in which I can't send email through my SMTP mail server for my domain at totalchoice for periods of 1 to 5 minutes. before and after those periods, with no changes at my end,mail goes through normally. there is no problem in downloading mail.
the intermittent message i get from thunderbird is:
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The message could not be sent because connecting to SMTP server mail.tchester.org failed. The server may be unavailable or is refusing SMTP connections. Please verify that your SMTP server settings are correct and try again, or contact the server administrator
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i can get this message ten times in a row, and then the eleventh time i try to send a message it goes through.
sometimes, though, i have to wait five minutes or so before a successful send. for example, after having messages go out without problems for the last three hours, now at 11:10 p.m. PST 12/23/12 it failed ten times in a row. I waited one minute, and it failed another ten times in a row. I waited another minute and it failed another ten times in a row. finally, at 11:17 p.m., it sent.
During the times it failed, my internet connection was fine, and I could download any emails received by my mail host at totalchoice, which points to the totalchoice outgoing mail server as the problem.
this is the third time in the past ten years in which this has happened. one year it got so bad i gave up and switched to another outgoing mail server for a while. i've never experienced such problems in using any other outgoing mail server.
years can go by and everything works fine, and then suddenly the problem recurs, as it did starting about a week ago now. it looks like the last time this occurred was July 2011 for a few weeks. at that time, i wondered if the mail server load was too high, but kris found that the load of my shared server was not high during those times.
twice before i've opened a ticket, but the help desk people didn't experience the same problem since it is intermittent, so i couldn't get any resolution other than to blame a "temporary glitch" at my totalchoice mail server.
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hence i'm posting to the forum to see if anyone else has experienced this, and if there is a resolution.
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i found two webpages discussing what appears to be a similar problem:
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i occasionally (several times a week) have this same problem on dione. if i try resending once or twice, the message always eventually sends.
https://docs.astro.columbia.edu/ticket/402
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After years of working well, 3 days ago Thunderbird began to intermittently fail to connect to smtp server. Usually, after 3 or 4 attempts e-mail can be sent.
http://forums.mozillazine.org/viewtopic.php?f=39&t=627156
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it seems like the main suspect is an intermittent server problem at totalchoice, but intermittent problems are very hard to track down.