Due to a minor problem I have uninstalled and reinstalled ArcGis Enterprise.
In the uninstall, I erased all traces left by ArcGis: the folders on the C drive. The directories inside ProgramData and ProgramFiles were deleted, I even manually cleaned the Windows registry removing all traces or so I think.
Installing iso ArcGIS_Enterprise_Builder_Windows_1091_180077
The installation completes successfully, open the browser with the ArcGIS Enterprise Setup Wizard, before I open Software Authorization for ArcGIS Server, and successfully authorize my software.
I continue with the ArcGIS Enterprise Setup Wizard, follow the steps, and upload the license .json file. So far everything perfect.
I follow the next and next steps, I get to finish and…. process stops at step
1) environment validation.

Creator or advanced user type, this is the third time that I do everything from scratch, and in no previous step did it ask me to configure the webadaptor again, unless even though Arcgis Builder was uninstalled, continue anyway the webadaptor installed on the system... check the panel control and everything was uninstalled.
What should I do? =(