420 4.2.0 Transient Failure during recipients lookup AmbiguousRecipientTransientException

I'm also in discussion with MS support more than 3 weeks and it makes me crazy ...... i don't get why they don't want just delete these duplicated guest accounts, i already removed them but still see them in PS as duplicated contacts and basically nothing can be done from my side.

and only i can hear from support is that i need to wait for EX1015484 to be solved, after that i hear that it does not help everyone, and finally i hear that i will be contacted by another specialist soon, this is ridiculous......i cant send emails to clients.....

I've never been so disappointed in MS service.

Hi Alec,

yes, you have to go through a bit of a pain with MS L1...

First I suggest you ask that L1 engineer, which workaround he proposes to get the mails delivered to your contacts, when EXO can't deliver because of the duplicates..?

Second, move all recipients from CC to TO, and also add the manager and the tech advisor.

Third, insist that your case shall be escalated to L2 as this situation has already been solved for other cases, despite the fact that the bug is not yet solved and understandably will still take some time. That said, MS can't expect their customers to sit and wait and halting parts of their business until the bug is solved.

I hope this helps a little bit!

Fingers crossed, cheers, Alex

Hi Per,

Your case got closed without removing the duplicates?

Re-open the case and move all recipients in the case mail from CC to TO, and also add the manager and the tech advisor.

Insist that your case shall be escalated to L2 as this situation has already been solved for other cases, despite the fact that the bug is not yet solved and understandably will still take some time. That said, MS can't expect their customers to sit and wait and halting parts of their business until the bug is solved.

I hope this helps a little bit!

Fingers crossed, cheers, Alex

Yes, i did reopen the case and once a week, sometimes twice a week i get mail from #R in Microsoft that they are working on the case, or that they have raised a request to the back-end team. I wounder how many back-end team they have? Its frusterated, but its only been two months, so....

Hi Per,

I'm feeling with you...

I wonder, if we were having the same "R" on MS... ;D

Hello Alex,

This is R from Microsoft 365 Support Tier 3.

I already created an escalation for this ticket to Product Engineering and still waiting for an update. Just to set your expectations, Product Engineering can take several days to respond and attempt to resolve a ticket. If you have any questions moving forward, don’t hesitate to reach out to us. We will keep you updated on Product Engineering's findings.

We thank you for your utmost cooperation and understanding. Have a great day!

***IMPORTANT NOTE:***Our support is a break fix concerns, and we would not be doing any Root Cause Analysis (RCA), deployment, change request in the product design, and scripting of PowerShell commands.

My response:

Hi R,

I do understand that complicated situations take their time, but in this case, it’s a known situation already solved multiple times. So, this should be an SOP and being easily to solve in short term.

I also understand that PG and OPS may take all the time they like, keeping customers waiting until they can again communicate with their partners and customers.

But if we (customers and support partners) take more than 3 days to prepare information and answers to your questions, cases are simply closed, quote:

Please be reminded that when the ticket reaches 3 days without any response, we will automatically archive the case on our end.

Imagine your car is not working properly, you can’t drive to your beloved ones, and the mechanic just tells you, “it may take some time until my workmates starts putting in the screws again….”

No offense, I know you’re just the one who transports the information.

I’ll go now and transport the information too…

Looking forward to some positive news on Monday.

Have a nice weekend!

On Monday, they've basically fixed it... I'm still waiting for the customer's confirmation... ;)

I'm sorry, MS, for blaming, but currently developers, operators and L1 are not performing really well... :(

Every week there is an advisory or an incident resulting from an update...

Cheers, Alex