Potential Cause #1:
This user has not used Report Sender before and you have not installed the connected app.
Solution:
See our article on installing the connected app for instructions on how to handle the connected app change that Salesforce instituted in September 2025.
Potential Cause #2:
You've restricted logins somehow, which is incompatible with Report Sender.
Solution:
First, make sure that the user has the Report Sender Admin permission set assigned to their user. Report Sender must be able to log in as users to the Reporting API in order to get the report data. To see why the authorization failed, check the Login History on the User's record. Most commonly, this fails due to IP restrictions. From Setup, go to Users, then open the User who is having issues. Under Login History, look for unsuccessful logins and make a note of the error.
The most common cause is if you have restricted logins to certain IP addresses. If you have IP restrictions on a profile for a user that is using Report Sender, you'll have to add the relevant Salesforce IP ranges. View the Help article on Salesforce IP ranges and add the ones that apply to your organization, or disable Trusted IP ranges.
Many security settings can cause login issues, so please contact us if you're unable to resolve the issue with the settings.