Gmail IMAP Broken

Starting yesterday afternoon sometime, my IMAP access to Gmail from Apple Mail 3.1 has been broken. The IMAP account won’t go online. I can’t find any mention of this sort of problem on the internet. My Gmail works fine from their web interface.

I keep getting the following error:

2.74 NO [ALERT] Lockdown in sector 4 (Failure)

Here’s a sample log of what I’m seeing during the IMAP connection:

CONNECTED Dec 05 11:58:58.586 [kCFStreamSocketSecurityLevelNegotiatedSSL] — host:imap.gmail.com — port:993 — socket:0x15b46980 — thread:0x19e48820

READ Dec 05 11:58:58.769 [kCFStreamSocketSecurityLevelNegotiatedSSL] — host:imap.gmail.com — port:993 — socket:0x15b46980 — thread:0x19e48820
* OK Gimap ready for requests from 141.142.220.140 h19if2297183wxd

WROTE Dec 05 11:58:58.891 [kCFStreamSocketSecurityLevelNegotiatedSSL] — host:imap.gmail.com — port:993 — socket:0x15b46980 — thread:0x19e4ce00
1.74 CAPABILITY

READ Dec 05 11:58:58.973 [kCFStreamSocketSecurityLevelNegotiatedSSL] — host:imap.gmail.com — port:993 — socket:0x15b46980 — thread:0x19e4ce00
* CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA XLIST XYZZY

1.74 OK Thats all she wrote! h19if2297183wxd

WROTE Dec 05 11:58:59.025 [kCFStreamSocketSecurityLevelNegotiatedSSL] — host:imap.gmail.com — port:993 — socket:0x15b46980 — thread:0x19e4ce00
2.74 LOGIN billglick ********

READ Dec 05 11:58:59.448 [kCFStreamSocketSecurityLevelNegotiatedSSL] — host:imap.gmail.com — port:993 — socket:0x15b46980 — thread:0x19e4ce00
2.74 NO [ALERT] Lockdown in sector 4 (Failure)

Can anyone help me fix this? I presume it’s a problem on Gmail’s end, but I don’t know how to confirm that.