When using the 'Add members using their enterprise ID without sending invitations' method in ArcGIS Online, the interface becomes unresponsive instead of displaying an error message if the imported CSV file has many rows with blank fields.

Workaround

When using the 'Add members using their enterprise ID without sending invitations' method to add users to the ArcGIS Online organization, upload the CSV file with all of the required information. This allows the addition of members using their enterprise IDs with a CSV file. For more information, refer to ArcGIS Online: Add members using their enterprise ID without sending invitations. 

Steps to Reproduce