Website mail being blocked as spam by gmail

[xoggoth]

Seems sorted. Problem was not actually in the code in question but an email order code I had been testing with a wrong envelope that used same from emails etc.

[xoggoth]

Checked some blacklists and not there.

Seems to be a Mail Channel support I can email:
https://mailchannels.zendesk.com/hc/...-blocked-error

PS On Monday! Why does my F* little website always go wrong late on a Friday evening??

[xoggoth]

Have been using gmail (class.phpmailer.php) in Worldpay and Paypal callbacks for ages with no problems but suddenly no emails are being sent. Direct testing of code gives error: "From address failed Called Mail() without being connected "

Changed to use normal php mail instead of gmail and now emails are ok when sent to my BT address but still fail if sent to any gmail address. Message returned to sender says it's blocked. Link takes me to a Mail Channels insights page that says it was blocked due to spam content. There's nothing spammy about the messages, just usual customer order details.

Any ideas why? Ta.