I've been using zoho mail for about 2 years but all of a sudden I seem to be unable to send emails to some recipients. THe email gets sent and then I receive the following error:
- INVALID_ADDRESS, ERROR_CODE :550, ERROR_CODE :Please turn on SMTP Authentication in your mail client.
sender-of-o51.zoho.com [135.84.80.216]:21143 is not permitted to relay
through this server without authentication.
Searching the internet points me towards missing MX records but my records have been working fine for quite some time now. Just for the sake of completeness I have now setup SPF and DKIm records too as well as a _dmarc record.
Still, slightly confused as my mx records do end in zoho.com and not zoho.eu as the help page instructs me.
Would someone please be so king to verify the MX, SPF, DKIM and _dmarc records for phoenixsolutions.nl?