Connection timed out when signing in to ArcGIS Pro via web browser

Description

When launching ArcGIS Pro, the application redirects to a web browser to sign in with the necessary credentials. Attempting to sign in fails, with the connection timing out.

Cause

The following may prevent signing in via the web browser:

• The web browser's proxy settings.
• The organization's IT has browser-specific restrictions in place.

Solution or Workaround

For ArcGIS Pro v2.8 and above

Disable the browser sign in via the ArcGIS Pro UI.

1. On the ArcGIS Pro home page, click Settings > Portals.
2. In the Portals menu, uncheck the Sign in using browser checkbox.

For ArcGIS Pro v2.7.2

Disable the browser sign in via the Windows Registry.

Warning:   
The instructions below include making changes to essential parts of the operating system. Esri recommends performing a backup of the operating system and files, including the registry, before proceeding. Esri cannot guarantee results from incorrect modifications while following these instructions. Exercise caution. Consult a qualified computer system professional if necessary.

1. Click Start > Run.
2. Type regedit in the Open box, and click OK.
3. Browse to the following registry key:

HKEY_CURRENT_USER\Software\ESRI\ArcGIS Online for Pro\SignIn

4. Search for and right-click the SignInFromBrowser registry key, and click Modify.
5. In the Value data field, change the value to 0, and click OK.

Note:
To re-enable, set the key Value data to 1.