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Emails being blocked based on IP Address

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Posted on by mdowst

I have a couple of flows that send emails from an internal Office 365 account to users in the same tenant. A few days ago all my emails stopped being received by the users. According the flow's history they are being sent. I logged into the Outlook web app as the account sending the emails and discovered a whole bunch of NDRs. The NDRs state, "Remote Server returned '550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP." I can send an email from the web app to the same user, it just fails when being sent through the flow, so I'm assuming that is the IP address that is blocked. Does anyone have any thoughts on how to fix this, or a possible workarounds?

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v-alzhan-msft on at

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Hi @mdowst ,

Does your issue still exists?

I have never encountered the issue that you mentioned and couldn't provide a solution currently.

I would make a more test and would reply here once I could find the reason and the solution.

Best regards,

Alice

Community Support Team _ Alice Zhang
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

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mdowst 7 on at

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I did some more testing, and confirmed it seems to be isolated to a single user. According to the Office 365 documentation I found, it looks like this can happen when you are using a preview license. I'm attempting to build and test this automation in a demo tenant, so that may very well be the cause of my issue.

If you must send email from these low reputation IP addresses before you can purchase licenses, contact support to request an exception until you're able to purchase licenses.

https://docs.microsoft.com/en-us/Exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-online/fix-error-code-5-7-700-through-5-7-750

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chcop 19 on at

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Hi from yesterday with all O365 demo cdx.transform.microsoft.com we have the same error 550 5.7.708 for all emails sent from Power Automate.
No problem if we try to send an email directly from Outlook.
We reproduce this issue with 7 different O365 demo tenants (90days or 1 Year)
The flow is very simple : only one action "Send Email (V2)"
In Outlook error :
admin@M365x849758.OnMicrosoft.com
Remote Server returned '550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP. For more information please go to http://go.microsoft.com/fwlink/?LinkId=526653 AS(7171) [MRXP264MB0854.FRAP264.PROD.OUTLOOK.COM]'

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FrankChenMSFT Microsoft Employee on at

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Hi @chcop , did you get your problem solved. My 1 year demo tenant created from demo.microsoft.com tenant got the same issue. it was working a few days ago. all my Outlook 365->"Send Email (V2)" action got failed with the same error message as your showed. did you have to do anything to fix this issue?

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