Running this by our support partners and provider as well, but figured I'd post here as well....

We access a 3rd party website for some data daily, and have done for many years. But lately, we seem to be getting issues with getting to the site.

Windows

All browsers fail to connect. Can ping and tracert perfectly fine. In Wireshark captures, can see the server sending SSL responses back to us.

Linux VM - run on my office desktop on the same network

Chromium fails to connect. Firefox connects fine.

We contacted the 3rd party and they cannot see any issues from their side. 

Odd thing is, both times its been really noticeable, has been a Friday. Starts off with a single user not being able to connect, then 10mins later everyone is unable to connect. Via mobile data, site is fine.

Then after a couple of days it all comes right again. 

Tried different DNS, new laptops, Intune devices, non Intune and so on but all same issue. Tried turning off IPv6, no change. 

So... what am I missing ?