As for timeout; if an endpoint does not provide 200 status code within 10 seconds, retry is scheduled and that request is considered as failed, more here.
Also, I noticed that in Postman the network icon is in “red state” for your endpoint, could you hover over it and check what does it say?
With a valid SSL certificate, I got this icon (on hover it shows all details)
If it can help in the meantime, with reqbin I have for headers:
Set-Cookie: JSESSIONID=FE1296D32BEDAB60D14990F76291A7BA; Path=/vplanning; Secure; HttpOnly
Cache-Control: no-cache, no-store, must-revalidate
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Connection: close
Content-Length: 0
Date: Mon, 21 Dec 2020 18:03:53 GMT
for "raw"
HTTP/1.1 200
Set-Cookie: JSESSIONID=FE1296D32BEDAB60D14990F76291A7BA; Path=/vplanning; Secure; HttpOnly
Cache-Control: no-cache, no-store, must-revalidate
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Connection: close
Content-Length: 0
Date: Mon, 21 Dec 2020 18:03:53 GMT