Thought I can provide a little information, as I continue to encounter this problem.
Teams web app, after logging in, makes four empty POST requests to this URL https://csp.skype.com/?ring=4&policy=enforced&version=1.1.8
Here are the headers
Accept
text/html,application/xhtml+xm…plication/xml;q=0.9,*/*;q=0.8
Accept-Encoding
gzip, deflate, br
Accept-Language
en-ZA,en-GB;q=0.8,en-US;q=0.5,en;q=0.3
Connection
keep-alive
Content-Length
3139
Content-Type
application/csp-report
DNT
1
Host
csp.skype.com
User-Agent
Mozilla/5.0 (X11; Ubuntu; Linu…) Gecko/20100101 Firefox/61.0
The server at csp.skype.com will return a 504 or 502 response after ~65 seconds.
<html>
<head><title>504 Gateway Time-out</title></head>
<body bgcolor="white">
<center><h1>504 Gateway Time-out</h1></center>
<hr><center>nginx</center>
</body>
</html>
