Lots of BYE Courier-IMAP server shut down by signal. errors

[#1]

I use (on different computers and tablets and phones) several different email clients (apps) to access my incoming PlusNet email, all using IMAP. They all suffer delays and disconnections, some coping with unexpected disconnections better than others. All the ones where I can see a trace of the IMAP network traffic keep ending with the same response, * BYE Courier-IMAP server shut down by signal. What does it mean? How can I (or PlusNet) get my email to operate without long pauses to recover?

From the email client with the easiest-to-see tracing, here is a not untypical fragment from its log data which is then followed by the network connection to the server being lost.

[16:59:02] IMAP4> 426 UID STORE 49440 +FLAGS.SILENT (\Seen)
[16:59:02] IMAP4< 426 OK STORE completed.
[16:59:08] IMAP4> 427 UID FETCH 49441 BODY.PEEK[]
[16:59:08] IMAP4< * BYE Courier-IMAP server shut down by signal.

I have fed the text into a world-famous search engine, and it finds the BYE message (only) in what looks like an old version of the Courier mail server. I don't think the problem is with any timeout parameters I can set: as you can see in the trace, it's just 6 seconds between the 426 OK response and the un-numbered * BYE response.

In case it helps: imap.plus.net, SSL enabled and using STARTTLS command, port 993, with an appropriate PlusNet mailbox name and password.

Is PlusNet perhaps using an out-of-date version of the IMAP mail server?

 - Mark

[#2]

I have been getting time-outs a lot lately (as well as odd out-of-order messages) when checking my IMAP inbox. They mess up my folders in different email clients on different systems.Today I was getting those BYE messages too and decided to store separately and delete around 1500 messages from my Inbox to reduce my messages on the server to 400 messages to reduce the pressure. Now Thunderbird is stuck in a loop, connecting, deleting, downloading, idling, timing out and re-connecting, and the number of messages on the server remains unchanged or may even be going up! Webmail is not terribly functional probably because of the same server issues. I am not sure if leaving this until late at night would help. In any case, these volumes of email should be negligible these days and didn't seem to cause problems in the past.

[#3]

Hi @glocal, thanks for getting in touch and I'm sorry to hear you're having issues when trying to access and manage your mail recently. I'd maybe suggest if you're looking to manage your mail to look into deleting the mail from the webmail if you haven't tried already. This can be done at mail.plus.net and anything deleted from the server side should then remove on your email client once the client re-syncs. If you've already tried this and this is where you're seeing the mail disappear and return in a loop then I'd suggest completely closing Thunderbird whilst you're in webmail managing and then re-open it via the client after.
Hopefully this helps with the issues you've been seeing and please let us know how it goes.

[#4]

On login, squirrelmail returns:

ERROR:

ERROR: Connection dropped by IMAP server. Query: SELECT "INBOX"

and when I re-try,  I get:

ERROR:

ERROR: Connection dropped by IMAP server. Query: STATUS "INBOX" (MESSAGES UNSEEN RECENT)

The standard webmail behaves erratically and eventually times out. It is a mess really. Back to Thunderbird. At least with Thunderbird I know where the messages are and can keep backups.

[#5]

I have the same problem is there a fix for this

[#6]

I am also getting the same issues and have done for months.

I have tried 6 different email clients and while POP3 works fine, IMAP always gets disconnected. Squirrel Mail and the Webmail both disconnect with IMAP errors as well using Chrome, Edge and IE11 and they are very slow.

I have been getting emails telling me my mailboxes are going to go over 1Gb soon (currently at 944Mb) and there is no way for me to delete a chunk of the older ones (I usually have the last year and a half still in my mailbox for work reasons).

I use POP3 on my desktop PC but leave messages on server, then I trim the ones I want using an IMAP connection (Outlook only lets you keep emails on server for 1-100 days if you have the remove from server selected. I need to have emails for a longer time so I can refer to them on the move.

I have an old Force9 account, is this what is causing internal IMAP errors? I use the imap.force9.net:993 server but have tried all the other ones (imap.plus.net) as well but they all error out after no time at all. 

Cheers

[#7]

Thanks for your post @falken and welcome to our Community Forums.

I'm sorry to see you're getting IMAP errors. 

These type of errors wouldn't be anything to do with a specific account, we're aware we have issues with IMAP/webmail we're working on getting to the bottom of, but I can't say when this will be sadly. Apart from using a POP3 mail client or Squirrel Mail Here try the steps Here which may improve the performance.

[#8]

Hi Gandalf, thanks for the quick reply. Tried that but I keep getting the following error whenever I try to view my Inbox.

It does the same for Sent Items, but not Deleted Items or Junk Mail folders. I can see a draft email in the Draft folder as well.

cheers

[#9]

Thanks for getting back to me @falken

Ah fair enough. Sadly there's not much more I can say apart from bear with as it's a problem under investigation. 

[#10]

Which email client are you using that provides that level of IMAP tracing?

[#11]

In basic webmail I get this:

ERROR:

ERROR: Connection dropped by IMAP server. Query: EXPUNGE

Also, none of my email clients are able to download email from the IMAP server, the last status from the server is Courier-IMAP server shut down by signal 

iOS Mail on my iPhone and iPad do seem to work okay though, but if they stop working with Plusnet IMAP, then this issue will be critical for me and - I'd guess - other Plusnet customers.

Is there any ETA on when this issue will be resolved?

[#12]

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@giskard wrote:

Which email client are you using that provides that level of IMAP tracing?

---

For tracing, I use Sylpheed. It's far from perfect, but it's free, works on Windows and on Linux, and has clear and easy-to-find IMAP protocol tracing.

The Tools > Log window command shows the trace data. Note that when it gets confused about the connection to a server, it helps to recover by clicking the offline-online button at the bottom twice, so that you don't have to wait for a few minutes time-out before it knows to start again with a new IMAP login.

 - Mark

[#13]

Thanks, downloaded and tried it out, doesn't work but then I think I'm experiencing major issues with Plusnet's IMAP email not to mention that my broadband connection has coincidentally developed a fault and keeps dropping connection.

Thank <insert-diety-here> for mobile data tethering, but am hoping PN and BT sort out my connection issue very soon.

Moderator's note by Dick (Strat): Full quote of preceding post removed as per Forum rules.

[#14]

Another person getting this same issue.

I've been having problems with Plusnet's Mail for months now and it's suddenly seemingly got much worse.

Switching WiFi/Internet connection has no bearing, the ports are all open on my device and I have this problem on multiple devices.

I've traced the communications between by client and the imap.plus.net server and I'm also getting:

* BYE Courier-IMAP server shut down by signal.

On this particular attempt the client tries to connect in total 7 times with a 2 minute timeout before finally connecting after 15 minutes. It can go for quite literally hours without getting a connection.

The connection is so unstable that any movements/deletions/changes to my email folders or messages are not actually reflected in my inbox - ie. any deleted or archived emails appear back in my inbox even if I delete, move or archive them several times.

It's an incredibly frustrating problem.

Plusnet: Wonder if you'd be able to shed any light on how long Plusnet have been aware of the problem, and how long it's likely to take before being fixed?

[#15]

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@UncleDave wrote:

... and how long it's likely to take before being fixed?

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Exactly, but I am not hopeful. As a PN subscriber for many, many years I know there are certain issues PN will simply ignore for ages. Eg secure connections to email servers was discussed for over a decade before it was implemented.