OWA - Reply all limited to ~23 recipients?

[papski2]

Good morning

Today we have noticed that OWA, when you click reply all on the email with a lot of recipients (in our case ~60), the drat is limited to around 22 - I did look at this draft through outlook app to confirm that it is not just weird graphical glitch and indeed it shows only 22. When you do the same through outlook app it works just fine. Same for mobile OWA. We checked every browser and same issue. Is that just our tenant or everyone else is seeing this?

[#2]

@papski2got a similar issue on two of the tenants I'm managing. 117 recipients on a sent email with BBC but only showing 16 when the user try to reply or to verify the recipients list.

Looks like there's a limitation on the OWA aplication. I've opened a case to MSFT and I'm waiting response to confirm this behaviour.

BTW i'm waiting an answer by client-side if they can see the complete recipients list on the Outlook heavy-client and Outlook on a mobile device, to confirm my suspicions.

I'll try to answer this as soon i got it confirmed.

[#3]

@Gabe Bratton might know something about this.

[#4]

@papski2 

I'm not aware of any Known Issues with recipients.  I sent this along to my peer who covers OWA, @AmirHaque-MSFT in case he knows of any issues.  As far as I know the recipient limits are what are documented here, Message size and recipient limits in Exchange Server | Microsoft Docs.

Maximum number of recipients in a message

500

Mail flow > Receive connectors > More options   > Organization transport settings > Limits Maximum number of recipients

Cmdlet: Set-TransportConfig Parameter: MaxRecipientEnvelopeLimit

[#5]

@Gabe Bratton @Amir Haque

We have checked other email thread with over 70 recipients and same thing is happening, but this time OWA was only replying all to 45 instead of 70.

EDIT: I have some people from spiceworks and reddit saying they have the same issues with OWA cutting users when using reply all.

[#6 · Accepted solution]

Update: This issue has been resolved. It was listed on SHD as EXO OWA SI: EX222686 for affected tenants ...

Thanks @Gabe Bratton for looping me in. This is a known issue at this moment. A bug is currently open with OWA Team & worked upon for root cause determination & a possible fix. 

[#7]

@AmirHaque-MSFT 

Thank you sir, this helps :)

[#8]

@AmirHaque-MSFT 

Issue is still not resolved, on top of that OWA doesn't even show all recipients in the messages, before at least it showed them all.

EDIT: Looks like after 5-10min of keeping OWA open the issue looks fixed along with showing all recipients on delivered message. Thank you Amir