Server not Responding

Server not Responding

8:30AM EST 3/24/16 - Trying to set up a new client. SMTP and IMAP servers are not responding when my email client tries to connect. Tried several clients (outlook, emclient). No luck. Diagnostics check OK some of the time. Very erratic. Strangely, works on my mobile.
smtp.zoho.com  465 (& 587) - use SSL/TLS if available (also Force SSL/TLS)
imap.zoho.com  993   use SSL/TLS 

Results erratic - server sometime responds. "Fix Server" option in emclients says Settings have been fixed. Still does not work.