How to resolve the web server failed to respond within the specified time 500 The request timed out
Issue Description
Azure AD SSO login failure: Failed to connect to login.microsoftonline.com on port 443; couldn't connect to the server
Root Cause
Proxy blocking the login.microsoftonline.com website.
Resolution
Add the Azure portal URLs to the proxy bypass list.
The URL endpoints are specific to the Azure cloud where your organization is deployed. To allow network traffic to these endpoints to bypass restrictions, select your cloud, then add the list of URLs to your proxy server or firewall.
Note: We do not recommend adding any additional portal-related URLs aside from those listed here, although you may want to add URLs related to other Microsoft products and services. Depending on which services you use, you may not need to include all of these URLs in your allowlist.
Azure portal authentication
login.microsoftonline.com *.aadcdn.msftauth.net *.aadcdn.msftauthimages.net *.aadcdn.msauthimages.net *.logincdn.msftauth.net login.live.com *.msauth.net *.aadcdn.microsoftonline-p.com *.microsoftonline-p.com
Azure portal framework
*.portal.azure.com *.hosting.portal.azure.net *.reactblade.portal.azure.net management.azure.com *.ext.azure.com *.graph.windows.net *.graph.microsoft.com
Account data
*.account.microsoft.com *.bmx.azure.com *.subscriptionrp.trafficmanager.net *.signup.azure.com