Scan to email stopped working

Scan to email stopped working

Hi, I have an HP OfficeJet Pro 8610 with a function for scanning to email. For months it's been working fine and I've been able to scan documents which then get emailed to my zoho account. In the last few weeks something has changed, I now get a 'Protocol error. This server is not supported' message. I've reset the printer to factory defaults, no change. Using a different email provider works. Using a different zoho account does not work. I've tried all variations of ports 465, 587, SSL, TLS etc - all fail. Can you help? Has something changed your end recently.

Kind regards,
Phil