Error: Invalid username or password. Login is case sensitive. You need to be registered
When logging into ArcGIS Online, even with a current ESRI Global Account, the following error message is displayed:
"Invalid username or password. Login is case sensitive. You need to be registered."
Your ESRI Global Account is not registered or linked to ArcGIS Online.
Solution or Workaround
Before signing into ArcGIS Online for the first time, your ESRI Global Account needs to be registered with ArcGIS Online by clicking the corresponding link on the Web page: