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Community Champion

Outlook 365 Web Mail Broken?

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We think we’ve discovered a problem with Outlook 365 (web mail) when trying to reply to students through a Canvas Notification. Something is not allowing the proper formatting for the recipient address in Outlook. Through several back-and-forth conversations with Canvas Support we think we’ve narrowed it down to a Microsoft problem. Not 100% certain, but that is our best information at present. Canvas engineers are aware. There is a work-around for until this is resolved: utilize the Outlook desktop client rather than the web client. It works fine.

Has anyone else seen this?

1 Solution

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Community Team
Community Team


We did reach out to Microsoft based on your reports and heard back from them that they were able to resolve the issues. We’re happy to hear it seems like it is working again for you. As always, let us know if and when something doesn’t seem to be working correctly. Thanks for being a part of the Community!


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37 Replies
Community Coach
Community Coach

Hi rgibson1,

I have actually had a bit of a discussion in another thread over here Canvas with Outlook, though we didn't narrow down if this was the web version or the desktop version, definitely sounds like it could be related.



Community Coach
Community Coach

I can confirm we are seeing the same issue.  At first we thought it was limited to using Safari and web access to Office 365, but I am also seeing the issue with Chrome as well, although not exactly presented in the same way.  Also confirmed that things still work fine using Outlook mail client on my Mac.  

Thanks for sharing information that it's likely a Microsoft issue. I'm hoping Instructure is talking to them about it.


They aren't. They closed my ticket and informed me to open a case with Microsoft.

Community Participant

We are seeing the same issue with Office 365 mail. The desktop client (so far) is working.

Community Participant

This is a problem at our institution as well.  Webmail cannot reply but desktop client can.

Community Member

I'm the O365 admin for our school, and we are seeing this same issue here as well.  Desktop Outlook clients can respond to Canvas notifications just fine, but in Outlook on the Web, they do not even attempt to send.

Furthermore, I can copy/paste the lengthy reply-to address, paste it into the "To:" field, and it will highlight itself in red showing that it will not be able to send.  If you try sending, it will not even do so, the "Send" button just does not respond.  But, if I truncate the address down to 93 characters or less, it no longer is in red, and it can be sent. (Albeit bouncing, but it will at least send.)


When is at the end, it will start having issues at 94 characters. However, if I come up with a garbage address with some domain that doesn't really exist, there doesn't seem to be that same character limit.


This same behavior is seen in Chrome, Edge, and Firefox all the same.

It looks like some weird combination of Canvas being the recipient address's domain, in addition to being over 93 characters long.

I'm fairly confident that if I open a Microsoft support case, they will see these behaviors and say that it isn't Microsoft's fault, even though it technically is.  (Microsoft support is very level-1-ish and they will not do any digging until you spend 1-2 days providing irrelevant logs)  If Instructure has any contacts they work with at Microsoft, I believe they need to get a conversation going with them on this issue, since it is clearly not specific to any one tenant based on the multiple reports in this thread and other threads.

EDIT: We received similar word from our Canvas support case as others, that their product team is aware and working with Microsoft on a fix.

Community Champion

Yes, we're seeing this in OWA as well. My response from Canvas Support:

Thank you for contacting Canvas Support. We have had other reports of users with Outlook who are unable to respond to Canvas notifications when using the Web App. We have reached out to Outlook to figure out why this is happening, as it appears to be an issue on their end. We have found that if you are using the Outlook app, you can disable the AutoComplete feature and that should resolve the issue. Here is an article that will explain how to enable/disable AutoComplete:

Community Team
Community Team

Thanks to everyone who has contributed to this discussion. Our Partnerships team has reached out to Microsoft about this issue, and our Product team is aware of it as well.

There appears to be a 92 character limit on Office 365 web for the email address.  Our reply address from a Canvas message in Outlook is 99.  The published email standard is 315 so Microsoft may have messed up. (Credit to Cliff Becker for discovering this).