Email Autoforwarding Issue

Seeing issue with emails forwarding into Syncro. We have a custom mailbox configured. We use an SMTP server to send out, and that works fine. The mailbox is on Microsoft 365 and we have the support@ mailbox configured to forward to the forwarding address, rsmbox-[ourdomain, etc]

Everything was working fine like this for months until today.

Today, several emails came in from clients and did not go into the ticketing system. If I open the support@ mailbox manually in 365, I see the emails were received. I checked 365 Message Trace and the emails were forwarded to the address, but they never came through on the related tickets.

Any ideas? Anyone seeing similar issues?


2 things come to mind. If you use a SMTP relay/smarthost, it can fail at that stage. We use Proofpoint and had some issues where it gobbled up emails because it randomly sent through the High Risk Pool of, which is not part of MS SPF.

Second issue is there is or was a bug that happened whenever batch invoices went out, for some reason, it triggered an incoming rate limit on emails for around an hour after.

No batch emails today, and no SMTP or smarthost.
Our setup is outgoing emails go through SMTP2Go, but outgoing is not affected.
Incoming emails go right to 365 - - and are forwarded to rsmbox-[…]

Per 365 message trace, the emails are getting forwarded to rsmbox-[…], but they never show on the tickets.

You’d need to reach out to support and see if they can trace it. Since it was handed off to Syncro, only support will be able to see where it went after that.

Syncro Support Case #00223274 is open FYI anyone who reads this

Crickets from Syncro support so far :frowning:

We just noticed that this is happening to us as well. The M365 message trace is seeing the replies go by and that they are sent on to, but they never appear in the ticket’s thread.

Good to know it’s not just us. Still haven’t heard from Syncro support.

Here’s an interesting thing we found. I decided to manually compare our message trace with what came in to Syncro. It turns out only one of our clients has been effected. They use their ISP email to do business. :roll_eyes:

We did a quick lookup of that ISP and they don’t have DKIM or DMARC enabled. Could it be that SendGrid (Syncro’s email provider) is rejecting these messages for that reason?

I have emails that haven’t gone through that have DKIM and DMARC enabled. I have some effected emails coming right from an address, which I know (and see, by the message details) has everything in order for SPF/DKIM/DMARC.

Good to know. I hope they are looking into this and will give us an update. It’s terrifying to think that random customers aren’t getting through. It really makes us look bad…

Right now we have techs keeping our support@ mailbox open in Outlook online in their browser to manually check that every email that comes in is landing in Syncro as a ticket reply. Pretty awful.

4+ days and haven’t even got a response on case 00223274 for this urgent issue.

I got a reply from Syncro a couple days ago, replied back with details they requested, and no answer.

However, I think I may have narrowed in down. Only Gmail/ Google Workspace users who use Outlook have their messages not going through to Syncro! I am investigating further.

Just a crazy guy here having a conversation with himself. I’ve been able to reproduce the issue. It’s messages that are sent from a Gmail / Google Workspace account from Outlook that aren’t getting through. I’ve looked at the message headers but haven’t narrowed down the cause yet, don’t have time really to dig into it. Maybe I will hire someone to figure it out and send the bill to Syncro support.

This just started happening with us starting a couple of days ago. Messages are same as yours, sent from Google Workspace account to an O365 support mailbox that forwards to to log the ticket. Wonder if there are any updates.

Check out the Syncro User Group on Facebook, there’s some info there floating around about it. No fix yet.