Additional non-parsable characters are at the end of the string

Error Message

When configuring ArcGIS Web Adaptor in a browser, the following error is returned:

Error:   
Additional non-parsable characters are at the end of the string.

Cause

This error occurs due to the following known causes:

• Connection to Web Adaptor not properly configured
  Connections to the Web Adaptor are not properly configured during the installation or are changed since the installation.
• Browser limitations
  Depending on the version of ArcGIS Web Adaptor installed, the Web Adaptor conflicts with the browser's security settings.

Solution or Workaround

Use one of the following solutions depending on the cause of error:

• Connection to Web Adaptor not properly configured
  Ensure the Web Adaptor is configured accordingly, mainly the Web Adaptor URL, the Web Context URL, authentication settings, or firewall settings. Refer to the Related Information section for more references.
• Browser limitations
  Configure the Web Adaptor in a different browser or disable the browser's security settings before configuring the Web Adaptor.

Alternatively, configure the Web Adaptor with the command line. Refer to ArcGIS Enterprise: Configuring the Web Adaptor from the command line for more information.