Random Failed Flows (REST API is not yet supported for this mailbox.)

[Questionasking]

Hi,

Every so often a few of my flows get the error below, however the flow then works the next day? should i be concerned?

{
  "status": 404,
  "message": "REST API is not yet supported for this mailbox. This error can occur for sandbox (test) accounts or for accounts that are on a dedicated (on-premise) mail server.\r\nclientRequestId: c5a3a334-70be-41fd-a4b4-6bd40b80973a\r\nserviceRequestId: 4a41e97a-66fe-4854-a0e6-a5de6eba4c52",
  "error": {
    "message": "REST API is not yet supported for this mailbox. This error can occur for sandbox (test) accounts or for accounts that are on a dedicated (on-premise) mail server.",
    "code": "MailboxNotEnabledForRESTAPI",
    "originalMessage": "REST API is not yet supported for this mailbox."
  },
  "source": "office365-ae.azconn-ae.p.azurewebsites.net"
}

[yashkamdar]

Hello Team,

I think the mail address that you are using is for accounts that are on a dedicated on-premise mail server.

Accounts that are on a dedicated on-premise mail server is not supported in the Send an email notification action.

I have made a test on my side to create a flow to send email notification to my office 365 mail address and don't have the issue that you mentioned.

Please refer the standard documentation available by Microsoft for this-

https://support.microsoft.com/nb-no/help/4462988/rest-api-is-not-yet-supported-for-this-mailbox-erro...

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[jordan_vtek]

I have this issue as well and it is not On Premise. In fact as of 5 days ago, it seems all my flows with an office 365 outlook connection have this error.

[cemastin]

We have the same issue as well, it started about 2-3 weeks ago. Flows working fine then out of nowhere we are getting this error and our email servers are not on prem so the error message does not match to the reality.

[cemastin]

Hi any other thoughts? I've escalated this with internal help and still no resolution. This is happening with users that are not on prem. 

[eric-cheng]

Hi @cemastin ,

I recommend logging a support ticket with Microsoft to troubleshoot the issue especially if it is causing an impact to your organisation.

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[cemastin]

I have and it is in process, however, no solution in sight as of yet and it's been over 2 weeks so trying to see if anyone else has found more info.

[eric-cheng]

Hi @cemastin ,

Have you tested recreating the connection and also testing with creating a connection with a different account.

Does the current account have a valid exchange online license?

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[cemastin]

Yes we have created new flows, and tested different submitters. Also tested to ensure aliases are not on prem. Something changed with Outlook and/or PowerPlatform that caused this because the same users were able to submit just fine before. We had not changed anything on our end.