Desktop login timout

I am unable to login via the desktop app, as it times out.

After entering my email, a window opens to redirect to our ADFS page but then disappears and Power BI locks up until it displays a timeout message.

This works fine from outside of my office, so we are positive that this is a firewall/SSL teardown issue.

The only page I can find with sites to unblock is this one.

https://docs.microsoft.com/en-us/power-bi/desktop-troubleshooting-sign-in

Unfortunately, that did not solve it.

This shows up in the trace:

DataMashup.Trace Warning: 24579 : {"Start":"2018-06-21T17:41:51.6762281Z","Action":"PBI.PQ.CloudDiscovery","Message":"{\"backendUrl\":\"https://api.powerbi.com/\",\"activityId\":\"0bc68a9c-589f-46c3-86c7-6de3947b8fc5\",\"requestId\":\"5e96228c-38ab-4562-91f5-843ca21670ce\",\"message\":\"The remote server returned an error: (404) Not Found.\",\"httpStatusCode\":\"NotFound\",\"exceptionType\":\"Microsoft.PowerBI.Client.Windows.Services.PowerBIWebException\",\"errorCode\":\"UnknownError\",\"errorDetails\":\"{\\\"error\\\":{\\\"code\\\":\\\"UnknownError\\\",\\\"pbi.error\\\":{\\\"code\\\":\\\"UnknownError\\\",\\\"parameters\\\":{},\\\"details\\\":[]}}}\",\"parentId\":\"9e6f0549-ef98-44e0-bcb5-79a6c2789bc6\",\"isError\":\"True\",\"sessionId\":\"0bc68a9c-589f-46c3-86c7-6de3947b8fc5\",\"deviceId\":\"a301f9e8\",\"userId\":\"b6789842-7d67-476c-af23-bb83a2397cd2\",\"isInternal\":\"False\",\"authenticatedUserId\":\"Unknown\"}","ProductVersion":"2.59.5135.601 (PBIDesktop)","ActivityId":"04d00c9d-e204-43d5-bed8-6a723535cc30","Process":"PBIDesktop","Pid":2036,"Tid":1,"Duration":"00:00:01.2011281"}

From the network admin:

"We know this is related to our firewall and SSL teardown as we are able to connect from external networks. We need to know what sites need to be exempt from SSL teardown. I have enabled trace logging but nothing in htere stands out."