Email errors - 550 Invalid sender (Please help)

Hi,

Over the last few days emails sent from my domain (including my website) failed citing:
AES128-GCM-SHA256:128 CV=yes: SMTP error from remote mail server “550 Invalid sender”

I’ve contacted my host who are passing the buck saying it’s a Cloudflare issue. I suspended Cloudflare on my site and emails are now working (and the host says they’ve changed nothing…)

I have 100s of emails listed as “Failed” in my cPanel Track Delivery that I desperately need sent out - they aren’t stored on my site as Gravity Forms has data deleted after submission for security. Is there someway to re-push these emails out from Cloudflare or do you have any other ideas?

Any help is greatly appreciated.

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I’m afraid that your host is giving you the runaround here - Cloudflare doesn’t provide SMTP services at all - so there’s no way Cloudflare would ever provide that error message.

If the SMTP is a subdomain of your domain, one thing to make sure is that it is “grey-clouded” in your Cloudflare DNS to ensure the SMTP traffic goes directly to your server: https://dash.cloudflare.com/?to=/:zone/dns

Ultimately - you’ll need to check what your e-mail clients are using as the SMTP server (normally this will be a hostname or an IP) and contact the hosting provider for that server IP (it will not be Cloudflare as we don’t do SMTP).

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Thank you so much Simon.
I’ve checked and yes the mail has a grey cloud with DNS Only.
I’m sorry I’m not sure what you mean with that link - https://dash.cloudflare.com/?to=/:zone/dns - should I insert my domain in there to check?

I didn’t think it could be Cloudflare but again they are claiming it is - here’s their response when I asked them for more info:

" This issue was due to Cloudflare having issues with propagating out the mail.mydomain.com.au as we saw this occur with another user that was using Cloudflare as well"

Could there be any truth to that?
Would really appreciate any help please, I think they ‘think’ because another person had the issue and they were with Cloudflare then it’s a Cloudflare issue :pensive:

If the SMTP hostname is grey-clouded, then I can guarantee that Cloudflare is not impeding your SMTP at all. Only your server provider can fix the issue - Cloudflare does not have anything to do with your mail server.

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Thanks Simon,

I’ll try them again. I just feel like they are passing the buck. They used to be a great host but their support lately is just to blame something else.

I’m also going to look into using a separate mail server (e.g Amazon SES) for my Wordpress site to send (Gravity) forms. If you have any hints or tips on a good mail server or one or even a setup style I should look into I’d appreciate any tips.

Thank you again.

I’d recommend something like Mailgun. I have such low usage that I’ve never paid for it. I route all my outbound WordPress email through that with the WP Mail SMTP plugin.

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Hi @simon

My host just wrote this back to me - would love your opinion please. I can’t find anyone else online having these issues which I would have thought I’d find if that were the case?!

"It looks as though the vendor for our Spam Filtering software had reached out and had a conversation with CloudFlare in regards to these issues that were present, and it looks as though CloudFlare themselves had reported an issue with the way that the records entered into their system.

They have since gone through and made some changes on their end that should have now resolved this problem."

If your provider has a ticket # where they spoke to us I’m happy to take a look, but fundamentally Cloudflare doesn’t provide SMTP services - so all of my previous advice still stands:

If the SMTP hostname is grey-clouded, then I can guarantee that Cloudflare is not impeding your SMTP at all. Only your server provider can fix the issue - Cloudflare does not have anything to do with your mail server.

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