Attempts to configure ArcGIS Web Adaptor for Portal for ArcGIS fail and the following error message is returned:
Error: Portal for ArcGIS configuration requires fully qualified domain name in the Portal URL
Portal for ArcGIS is configured using a domain name service (DNS) name instead of a fully qualified domain name (FQDN). Refer to ArcGIS Enterprise: Domain name service and fully qualified domain name requirements for more information.
Specify the fully qualified domain name (FQDN) of the machine when configuring ArcGIS Web Adaptor for Portal for ArcGIS. Refer to Step 4 of ArcGIS Enterprise: Configure ArcGIS Web Adaptor from the configuration web page for instructions. The format of the FQDN used in the Web Adaptor configuration page is as follows: