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Hi,
I'm testing "Email SMTP as a Service" that is in preview within "Azure Communication Services". I was so excited to hear about it because we've just done an Exchange migration to O365, and this feature will help mop up the remaining SMTP client apps without having to deploy any SMTP relay infrastructure.
It was very easy to set up and get working for 2 test domains.... BUT...
The instructions state that a Service Principal must be used as the user. And with this, the username must be in the following format:
<Azure Communication Services Resource name>|<Entra Application ID>|<Entra Tenant ID>
This makes for a super long username. Mine was 94 characters! It worked in one SMTP client software but others I've tested have character length limits such as 60 characters.
The 2 pipes (or dots), App ID and Tenant ID guids mean that the username has 74 characters before the ACS resource name prefix is added!
I thought it might work with a UPN as username, so I added a user to the IAM Role Assignment, but that didn't work, returning error code "535 5.7.3 Authentication unsuccessful".
Is there a workaround? Because without one, the use of this SMTP feature will be severely limited.
Thanks,
Jonny S
@Jonny Sharp Hi, thank you for reaching out. As you mentioned, this feature is in preview state currently. This means that we do not recommend the feature for production use as features are still being matured out into their GA state and there might be known bugs.
With that being said, let me reach out to the team and see if this is something they are aware of. I hope to reply back by mid-week.
@Jonny Sharp I have not forgotten about your ask. I am still in discussion with the product group. Please give me a little more time. Thanks
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(182.40000000000003, 40%, 27%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EDE%3C/text%3E%3C/svg%3E)
Did you do anything with this?
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(0, 55.00000000000001%, 10%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMM%3C/text%3E%3C/svg%3E)
We want information on this as well. Want to move our SMTP apps to Azure but most only support 50 character limit so it won't work as currently architected.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(163.2, 46%, 25%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EAT%3C/text%3E%3C/svg%3E)
Just wanted to raise that I think i'm facing similar issues using CMailGUI 0.04 as a test platform
I am having the same problem.. Is there any update?
We are cut at 64 characters
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(172.8, 54%, 26%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EJW%3C/text%3E%3C/svg%3E)
I have this same issue; the username is entirely too long for even a brand-new app we're installing. We are actually stuck at a 50-character limit.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(156.8, 62%, 25%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EBH%3C/text%3E%3C/svg%3E)
@brtrach-MSFT Did this user ever give you details to pursue this with the product group? I just ran into this exact issue today and will gladly relay my experience
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@brtrach-MSFT I have the same issue. Can you please give us an update?
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If it eeks anyone below the limit their are facing in their application, you are able to remove the dashes in the app/tenant ID. But I am also looking for this to be fixed to be able to reliably use this product. Most legacy apps requiring smtp auth were simply not built with expectations of usernames this long.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(313.6, 77%, 40%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ENG%3C/text%3E%3C/svg%3E)
next try..any updates ?
Is there any update on this? It's really annoying. Now i have to use a third party service.