Can't log in to my email today using Aqua Mail Pro

[cyberqueen]

This morning, I tried to log in to the two email accounts I check with Aqua Mail Pro.  I repeatedly got an error message saying "Error synchronizing mail, Authentication error: NO Login failed: Authentication failure."  On the list of folders, it says "Incoming server login error: NO login failed: authentication failure."  I've checked, and I have no trouble logging in to these same accounts using the email program on my desktop computer.  I check my email at least once a day with Aqua Mail, and this has never happened before. (I used to have Aqua Mail check for mail every X minutes, but several months ago I decided I would simply check manually rather than on a schedule.  That has not been a problem.)  I'm using Aqua Mail version 1.4.0.30 and Pro Unlock 1.0.12 on a Nexus 7 tablet running KitKat 4.4.4. 

[cyberqueen]

Thanks for your quick response.  Both are IMAP accounts at my university.  They're not Hotmail, Gmail, etc., not web-based.  I'm not sure what else to tell you.  On my desktop computer, I usually access them using the email client Mulberry, though I can also access them with PostBox or, I suppose, any other email client.  Until this morning, I've had no problem accessing them with Aqua Mail.  I might note that I use the same wi-fi network to access them on my desktop computer and on my Nexus 7 tablet.  Please let me know whether there's other information I should provide.

[cyberqueen]

Thanks for your continued help.  I checked all that you asked for, all is the same except that the security option chosen for Aqua Mail was SSL (strict check), which was the closest I could come to SSLv3 (in Mulberry) and SSL/TLS (in PostBox).  The port in all cases is 993.  This has been what I've used all along, and I've had no problem until today.  I don't know what's wrong.  I'm able to get mail fine in Mulberry and in PostBox (I checked that before writing the first time).

I've gotta run, but I'll check back here later this afternoon.  Again, many thanks.

[cyberqueen]

Thanks, Paris Geek, for your continued suggestions.  I tried all the security options except Not encrypted (since I wouldn't want to use an email program with no security).  None of them worked.  Until today, SSL (strict) worked fine--for months.  Today, none of them works.  I then downloaded and installed the new version, which I guess is not yet at the Play Store.  That didn't make a difference, alas.  I have no idea why this is happening.  I haven't had a problem with any other program on my tablet, nor am I having a problem getting email using either of the email clients on my desktop computer.   

[cyberqueen]

I went back to the email client that came with the Nexus 7 tablet.  I had used it before I switched to Aqua Mail.  I simply told it to refresh, and a bunch of email messages, including several from today, appeared in my Inbox.  I had no trouble reading them.  So I think that the problem doesn't lie with the tablet.  And I want to repeat that until today, I had no problem accessing my email with Aqua Mail.  I can't imagine what's creating this sudden problem, but it seems restricted to Aqua Mail.

[cyberqueen]

I'm almost afraid to post this message for fear of jinxing things, but I just tried again to access my email through Aqua Mail, and THIS TIME IT WORKED!!    I have no idea why it finally is working, but it is.  I wish I knew what had caused the problem, but I think I'll just be glad that it may have disappeared. 

Paris Geek, I'm most grateful to you for all your efforts to help me resolve this.

[Kostya Vasilyev]

Here is my guess (and sorry if I missed most of the conversation).

AquaMail supports a very secure method for logging in (authenticating), for IMAP. It's called CRAM-MD5.

This is an optional part of the IMAP spec, so it has to be "advertised" by the server, for Aqua to see it and try to use it.

Since it's the most secure method of logging in, Aqua will prefer to use it -- again, when it's advertised by the server.

Sometimes (actually, more often than I'd like to), IMAP servers are configured to advertise it, but it doesn't actually work.

In Aqua, you can turn it off: long press the account -> account setup -> Manual -> change "Authentication" from "Choose automatically" to "Prefer compatibility".

My guess is that your tablet's stock Email app doesn't support CRAM-MD5, so it worked -- and then the IT people either made CRAM-MD5 actually work, or turned it off again.

[cyberqueen]

Kostya, thanks for your response and the info about CRAM-MD5.  I suspect you're right that the tablet's stock email app doesn't support CRAM-MD5.  However, the rest of your explanation is less persuasive for two reasons.  One is that Aqua Mail has worked beautifully with the university's servers for months.  I don't know whether those servers use CRAM-MD5, but whether or not they do, there was no problem with Aqua Mail until the day I posted my message.  Also, I find it somewhat hard to believe in the coincidence that suddenly, out of the blue, the IT folks at my university fiddled with CRAM-MD5.  And even if they did, since Aqua Mail apparently works with servers that use it and servers that don't, why would suddenly turning it off make a difference?

[Kostya Vasilyev]

First, stock Android Email code does not support CRAM-MD5, that's a fact... but of course there is no way to tell with manufacturer specific, enhanced, versions.

Second, it takes two to tango -- and I wouldn't rule out the IT department first enabling CRAM-MD5 ("let's improve our network's security, oh, look, hash based authentication, that's cool") and disabling it or fixing it, after they discovered incompatibilities.

Just a theory, but...

Please understand that Aqua will always send the same authentication commands, same login, same password... it doesn't make stuff up on the spot (and there were no updates in the meantime). It's deterministic.

So something had to change outside of Aqua, that is, with the mail service. Knowing about CRAM-MD5, this was my guess. An educated guess, but still, only guess.

On the other hand, I don't believe in magic and evil fairies.

And I've seen many cases over the time of my working on Aqua where mail services (large and small) got changed and broken in various ways (and then sometimes fixed, sometimes not).

Just what comes to mind: Gmail, Yahoo, O2.pl, Apple's @me.com / @mac.com, Hotmail, QIP.ru, Yandex.ru, Telefonica.es, GoDaddy (my favorite)...

[cyberqueen]

Thanks, Kostya, for your reply.  I'd rather not ask the university IT folks whether they were messing with CRAM-MD5 on the day I had problems, at least, not unless it happens again.  For now, I'll just assume that it was a one-time fluke, one of Life's Little Mysteries. 

Let me say once again how delighted I am with Aqua Mail Pro.  Many thanks for this terrific program, and for your active participation in the forum.

[Kostya Vasilyev]

Yeah, I probably wrote too much there last night (a large cappuccino is to blame for that).

And since it's working again, well, what more could I wish for?

[Kostya Vasilyev]

Just to put a bit more perspective on this:

Verizon just messed up their SMTP server in same exact way.

http://www.aqua-mail.com/forum/index.php?topic=2631.0

There must be something magical about CRAM-MD5, maybe admins don't know how to perform testing after they enable it.