Q: IMAP for my office e-mail has stopped working

Not so fast—it only worked until Mail was restarted or authentication was required again for some reason (lost connection, whatever). As others have noted, there's clearly an underlying bug.

I too have this problem on a new Macbook Air with Lion. I cannot log into my imap account using SSL (port) 993. I keep getting asked for the passord and it keeps getting rejected. Turning SSL OFF and then back ON doesn't work. I run Mailserve for my mailserver and can log in fine using Snow Leopard on a MacPro, Macbook, 2 Mac Mini's and my iPod. Using SSL for the SMTP server and MD5 Challenge-Response for Authenticaion works fine. I had to turn SSL off in Mailserver (port 143) to get my mail.

This is such a problem for me I'd be installing Snow Leopard on the Macbook Air if it was possible.

Big thumbs down on Lion for me!

I just installed the 10.7.1 Lion update and this issue wasn't fixed, what **** is with Apple?

As noted earlier in the thread, the problem appears to be with one particular implementation of IMAP. A one-line change in the IMAP server source will resolve the problem. I convinced our IT guy to implement the patch and we've had no problems since.

Thanks for your response but I am not a programmer and have no idea how to make the one line change you suggest. Also you say a one line but what is the actual change, I see many lines in  your code?

Sorry—I should have been clearer. I'm not a programmer either. The person who maintains your office e-mail server would have to make the change. If that's you, I'm not sure what to suggest other than to bone up on IMAP or find someone who is familiar with it to give you a hand.

Worked for me, too!

Thanks Bruce and Tim

All, I believe I have resolved this problem with the help of Apple's engineers.  They have been very helpful.  I have tested and I can now receive IMAP messages immediately instead of having to restart Mail.  Steps to take:

1. quit Mail

2. make a copy of your /Users/~/Library/Mail folder (save to desktop as a backup)

3. remove the following files from /Users/~/Library/Mail

com.apple.mail.plist

Envelope Index

4. restart Mail

note: this basically wipes out mail as if it is a new reinstall

note: I removed LetterOpenerPro and reinstalled after this, but I don't believe it was a factor in the resolution. Hope this works for you (much kudos to Apple support!).

note: during testing, I created a new user account in Lion and the Mail app work properly.  I had to make the changes above to make it work for my normal user account.

I'm on 10.7.2 and I still have to restart Mail daily to get work IMAP email regoing.

Any chance there is a solution without starting from scratch with Mail? I have loads of other accounts, rules, archived mail. Don't really want to lose anything.

Thanks.

Solved!

For any of you experiencing connection issues with IMAP and Lion it has nothing to do with Mail preferences, recompiling IMAP Server or so.

This is a Mail.app bug, i've just waste all day at the office trying to sort this out: using tcpdump, connecting to the server using openssl, etc.

Mail.app tries to use AUTH PLAIN if available on the server, according to the RFC, this command must be followed by a base64 hash which it's total length must be divisible by 3. This hash is just a base64 encoding of our username and password.

So... the problem is that Mail.app does not add the necessary padding to this username + password so the hash length is divisible by 3.

So... how to just solve the problem??? Just change your password's length!! Add one or two character's (depending on your username and password length) so the base64 hash is divisible by 3. I found this solution by connecting to my imap server using openssl in the terminal by adding the padding manually.

Hope you find this usefull, I'm filing this as a bug so apple fixes it for any password/username length.

YOU-ARE-A-GENIUS !

It works ! Thank you so much !

After Lion install...My email was off-line.  I just had to take it on-line per instruction from  thomasfromstratford.  Issue solved.

I have my own mail server using Mailserve , I fixed the problem by switching my IMAP server to Dovecot.

The divisible-by-three email pw fix is working for me - thanks, Raul!