Default 'extra info' email content triggering gmail spam detection

[neekfenwick]

ZC 1.5.5f

Not sure if this is really a Bug report (it only affects people using gmail as their email host, I think), but I think it may warrant a change to the default Extra Info content in admin emails, which includes: New order email, Contact Us email, and a few others. If this is a real problem affecting others, I would suggest changing the default ZC email_collect_extra_info() function so that when EXTRA_INFO is included in emails, it does not contain any IP address or hostnames. If not, please move this to non-Bug forum, because I think it's still good info for some people.

Long story short.. the ip address and hostname included in the 'Office use only' section of emails generated by Zen Cart, when sent via a gmail account, tends to cause gmail to block the sending account because they look like spam, and your Zen Cart shop will be unable to send any emails. Not resolving this problem leads to the account being unrecoverably blocked for 24 hours at a time (due to google policy).

Just a heads up to anyone else struggling with this, we have had a few weeks of grief using a G Suite (gmail) account as our SMTP Email configuration in Zen Cart. Our account would be mysteriously blocked, and we would start to see this error message on the ZC web interface after trying to send an email:

"... has exceeded the Gmail sending limit by sending too many messages that were rejected as spam"

Looking into our g suite admin console for the User we're sending as (our EMAIL_SMTPAUTH_MAILBOX) we saw a red banner at the top of the screen with the same message and a 'RESTORE GMAIL' button that can only be used 5 or 6 times a year.

We did get a small number of emails sent back to us with the subject "Delivery Status Notification (Failure)" with the failed message attached.

We realised that there was a pattern to which messages failed, they were almost all in response to the Contact Us form on Zen Cart, or our replies to those messages. Both of these include the 'Extra Info' content. Once I removed that content, the problem went away.

I realise this only affects admin emails .. normal emails to customers don't include the extra info, so wouldn't trigger the spam detection. However it only took a few hours of our business operating normally (10 Contact Us messages a day, perhaps) to trigger the spam detection, then our gmail account was blocked, then all emails stopped being sent .. new order notifications, order update notifications, and a bunch of other order management stuff we've added to ZC.

Fix: Remove the ip address and hostname content from the emails.

Our workaround: We don't use that information anyway, so I have edited email_template_contact_us.html to completely remove the EXTRA_INFO block.

This was extremely painful to our business, with many support staff unable to contact customers for a couple of days, so I really hope this info could help someone else facing this problem :)