You may come across this error when attempting to connect a device to your Webmail email address.
"Missing +OK response upon connecting to the server: * OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE NAMESPACE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot ready."
This error is commonly caused by specifying the wrong port for a POP3 connection.
IMAP Port: 993
POP3 Port: 995
Use port 995 instead of 993 and try to connect your device again.