I added an external IMAP account a while ago which was working no problem.
Recently I have started getting an error each time to log into the Web client, saying there is a problem with the account. If I go into my preferences and try to delete the account, it does, but when I click on save I get the error "no such data source: 24de02f8-fb77-4887-ab18-2c186deed9f1"

If I go into the CLI I see the account

zmprov gds xxxx@xxxx.com

# name xxxx@xxxx.com
# type imap
objectClass: zimbraDataSource
objectClass: zimbraImapDataSource
zimbraCreateTimestamp: 20110602094412Z
zimbraDataSourceConnectionType: cleartext
zimbraDataSourceEmailAddress: xxxx@xxxx.com
zimbraDataSourceEnabled: TRUE
zimbraDataSourceFailingSince: 20111128082330Z
zimbraDataSourceFolderId: 67014
zimbraDataSourceHost: x.x.com
zimbraDataSourceId: 24de02f8-fb77-4887-ab18-2c186deed9f1
zimbraDataSourceImportOnly: FALSE
zimbraDataSourceLastError: system failure: Unable to connect to IMAP server: DataSource: { id=24de02f8-fb77-4887-ab18-2c186deed9f1, type=imap, isEnabled=true, name=xxxx@xxxx.com, host=x.x.com, port=143, connectionType=cleartext, username=xxxxx, folderId=67014 }, Connection timed out
zimbraDataSourceName: xxxx@xxxx.com
zimbraDataSourcePort: 143
zimbraDataSourceType: imap
zimbraDataSourceUsername: xxxx@xxxx.com
zimbraPrefFromAddress: xxxx@xxxx.com
zimbraPrefFromDisplay: X
But I can't delete it.

zmprov dds xxxx@xxxx.com xxxx@xxxx.com

ERROR: account.NO_SUCH_DATA_SOURCE (no such data source: 24de02f8-fb77-4887-ab18-2c186deed9f1)
I have restarted the the entire Zimbra server, but the error remains.