SharePoint Online Connection Issues

[Gary Griffin]

We are having some very strange connections issues to our SharePoint Online content.

From time to time users from across our network (50+ locations) experience a “Can’t reach this page”.

When the “Fix connection problems” button is pushed we get “The remote device or resource won’t accept the connection”.

Viewing details shows us “The device or resource …. is not set up to accept connections on port https”

The problem goes away in 9 minutes every time.

This only happens when a user is on our network. When connecting from off the network the problem is never seen. It would seem there is an issue with our network.

The outage seems to be limited to one machine at a time. If we login on another machine, while the issue is occurring, the user (with the same credentials) can connect with no issues. If a user unplugs from the wired network, on the machine having the outage, and connects to the wireless the issue goes away. The inverse is also true, switching from wireless to wired networks will clear the issue.

We have captured Wireshark and Fiddler logs. They both show the connection is indeed being refused from the Microsoft server.

This only happens accessing SharePoint Online ( *.sharepoint.com) and some of the related apps (OneDrive, People, etc.). The Admin link works just fine. All of the Office products seem to work fine as well as Video.

We are working with Microsoft Premier services and so far have been told by the SharePoint team that they do not see any issues on their end. The ticket has been moved to the Networking Team and we are waiting to here from them.

This has been going on 5 months.

Any help or ideas of what we need to look at would be great!

[#2]

I would recommend to review your network just confirm everything required to connect to Office 365 is correct (Ports, URLs, IP Ranges)...I would also recommend to check if something is wrong in the quality of your network connection

[#3]

Thanks for you suggestions Juan. We just finished up the network test/evaluation with MS and for the most part everything is Ok. We need more bandwidth (who doesn't) and some of our DNS settings in Europe were not perfect. But overall a pass with no real recommendations.

[#4]

I am having a very similar issue.  Did you ever come to a resolution and see this problem go away.  Our sites have 100 Mbps connections and we are never over utilizing them.  We thought it could be a DNS issue but when the issue would be occurring on a users machine we would switch their DNS to Google for testing and the problem would still exist.  Anything else you have done and gotten to work would be much appreciated.  We are using SD-Wan technology at all our sites and I thought that might be the culprit but I cannot narrow anything down on it that would be causing it. 

[#5]

We did finally find the issue that was causing this problem. It was our barracuda, there was a setting that was closing the connection after 9 minutes. Our fix was to let the traffic to Microsoft pass with no filtering. This can be challenging as MS changes these form time to time (mostly adding to them) but that is a different issue LOL. Once this was in place (the bypass) the problem never happened again.

Good luck

[#6]

Very interesting.  We have a Barracuda Web Filter as well but our SD-WAN is supposed to be bypassing the Microsoft traffic from going through there.  I am not 100% confident that is happening.  Did you bypass the traffic in the Barracuda by IP or by all the domains that Microsoft has? Thanks so much for your quick response. 

[#7]

We ended up using ip's, this is based on MS recommendations. During our testing we turned off the webfilter totally, this removed any doubt where the problem was. It took us what seemed like forever to get our security team in the loop as they only wanted to tell us it was not their issue LOL. We then used wild-card dns entries ( *.sharepoint.com etc.), once we got that working we switched to ip's. The ip's are something that we update/confirm monthly as they change some times.

g