In some instances, when adding an ArcGIS Online connection to the ArcGIS GeoEvent Server's data stores, the connection fails to establish, returning the following error message:
Error: Unable to generate token. [Invalid username or password.]
Depending on the cause, complete one of the workarounds provided to resolve the error.
Use the correct letter case for the login credentials
ArcGIS GeoEvent Server is case-sensitive when accepting credentials from ArcGIS Online. Resolve this issue by using the correct case for the username as in ArcGIS Online.
Add ArcGIS Online to the allow list to enable connection access
A proxy can prevent ArcGIS GeoEvent Server from communicating with ArcGIS Online servers. On the machine, navigate to the Start menu > Internet Options > Connections. Under Local Area Network (LAN) settings, click LAN settings to check if a proxy is used on the machine. If a proxy is used, ensure the ArcGIS user account has access to the internet by attempting to access the internet using a browser. The system administrator must grant access to the ArcGIS user account by adding the user account into the proxy server's allow list to enable the connection to ArcGIS Online. Refer to How To: Configure ArcGIS GeoEvent Processor to use an HTTP Client Proxy for more information.