As of yesterday SSL/TLS over IMAP appears to have stopped working on Slingshots mail servers?

STARTTLS (port 143) works, but a full SSL/TLS (port 993) does not.  Yesterday morning it did.

This problem is reproducible with both Thunderbird (PC) and K9-Mail (Android), and from both from a Slingshot broadband connection and externally (via 3G).

Thunderbird reports:
Error: An error occurred during a connection to imap.slingshot.co.nz:993.
SSL received a record that exceeded the maximum permissible length.
(Error code: ssl_error_rx_record_too_long)

K9-Mail reports
SSL-Protocol error:140770FC:SSL


Note that I set up according to the instruction here:
http://help.slingshot.co.nz/display/public/HELP/How+to+set+up+Slingshot+email+on+your+computer+or+device


Wondering if it's me - or if anyone else has seen this.

RaY