Logged on to Bigin today to find that I wasn't able to access or send any IMAP emails.  So I recreated the IMAP conneection (to my Fastmail account).  I can now read the Fastmail emails on Bigin, but when I try to send from Bigin I get an "Error While Sending Mail" error.  I'm sure the IMAP settings are correct.  Something down on the Zoho side?  A Fastmail issue?  Any ideas on how to check this would be much appreciated.