Dead in the water with Gmail — can't reach IMAP or SMTP

[Robio]

Hoping someone here has some ideas, because I'm all out.

Starting 2014-07-30, I began having periodic trouble connecting to imap.gmail.com, imap.googlemail.com, smtp.gmail.com, and smtp.googlemail.com.

As of 2014-07-31, I cannot download or send gmail AT ALL, on ANY of my gmail accounts in Postbox.

When I try to download, I see "Connecting to imap.googlemail.com..." in the status bar, then after 20 seconds or so, the "contacting" message just goes away without downloading the mail that is in my gmail inbox. When I try to open any folders, the same thing happens. I literally cannot get to any mail not already stored locally.

When I try to send, I see "Connecting to smtp.googlemail.com..." in the status bar, then I get a pop-up error stating...

Send Message Error: Sending of message failed.

The message could not be sent using SMTP server smtp.googlemail.com for unknown reason. Please verify that your SMTP server settings are correct and try again, or contact your network administrator.  Additionally, verify that your firewall or antivirus program is not preventing Postbox from sending email.

And yet, Postbox's Error Console shows no errors.

I have made no recent changes to setting prior to this problem developing, either in Postbox or at Google.

I do not have this problem with non-Google email accounts.

I do not have this problem using Apple Mail to reach the same accounts from the same computer.

I tried deleting Postbox preferences, no luck.

I tried uninstalling and reinstalling Postbox, no luck.

I tried adding a new account in Postbox for another gmail address I've never used Postbox to check, but couldn't complete the process because during setup I get the error "Settings, user name, or password could not be verified."

I tried changing my email password on one of my Gmail accounts, no luck.

I created a whole new user account on my Mac, launched Postbox in that clean account, and tried to create an account for one of my gmail accounts, and got the "Settings, user name, or password could not be verified" error.

I even tried opening Postbox for Windows on a Windows machine. There I did get an error saying "imap.gmail.com:993 uses an invalid security certificate," but I could bypass that, and Postbox still worked.

I've also rebooted my modem (thought maybe a dynamic IP change might help), rebooted my computer, and even zapped the PRAM.

I'm completely dead in the water.

Anybody have a suggestion or idea?

[Robio]

OK, so apparently this was all due to my IP address. I guess Google didn't like it or something. Turns out the problem started a couple days ago after rebooting my router. I rebooted again today, dynamic IP changed, and now everything's fine.

[Neo Code]

I got this in my gmail - switching to less secure did the trick

Hi xxx, 

We recently blocked a sign-in attempt to your Google Account [x...@gmail.com]. 

Sign in attempt details

Date & Time: Tuesday, November 1, 2014 6:06:06 PM UTC 
Location: Paris, France

If this wasn't you

Please review your Account Activity page at https://security.google.com/settings/security/activity to see if anything looks suspicious. Whoever tried to sign in to your account knows your password; we recommend that you change it right away. 

If this was you

You can switch to an app made by Google such as Gmail to access your account (recommended) or change your settings at https://www.google.com/settings/security/lesssecureapps so that your account is no longer protected by modern security standards. 

[Robio]

Thanks for the tip. I'll keep that in my back pocket in case this happens again.

[Matthew Holt]

I had the same problem. After noting your solution with the IP address. I noted I was using private internet access so my IP address was masked with whatever that software was making it look like. I turned off private internet browsing, so back to my actual IP address and the problem was immediately fixed. I was able to send mail instantly.