Invalid token error in ArcGIS Monitor when registering ArcGIS Server as a component

Description

When registering an ArcGIS Server as a component with ArcGIS Monitor 2023.3.1, the following error may be encountered, as shown in the image below:

Example:

An Error occurred while running the observer
Server machine
'https://machinename.domain.com:7443/arcgis/sharing/rest/community/self' returned an error. 'Invalid token'

Cause

This error may indicate that the credentials you are connecting with are not valid. Please, double-check your username and password, as well as the requirements to register ArcGIS Server as a component.

Solution or Workaround

It is important to note that the requirements to register ArcGIS Server as a component with ArcGIS Monitor depend on whether the server site is federated on unfederated:

• For federated ArcGIS Server sites, you must provide credentials for the ArcGIS Server primary site administrator account to register the site.
• For unfederated ArcGIS Server sites, you must provide credentials for an ArcGIS Server user account with the administrator role to register the site.