Is that account protected by MFA? If so, temporarily remove that MFA requirement or use another account that isnt using MFA and try that.
Hybrid Exchange Public Folder Access
I am in the process of working through a test plan after recently setting up hybrid Exchange with O365.
I have been trying to follow the steps outlined in this MS article, with a view to testing O365 user access to on premise public folders.
I've not managed to get very far in my lab however, as I am met with an "Access denied" error when attempting to run the following command, as part of the process:
.\Sync-ModernMailPublicFolders.ps1 -Credential (Get-Credential) -CsvSummaryFile:sync_summary.csv
The credentials I am inputting are my global admin creds for O365.
I am able to connect to ExchangeOnline via Powershell with the same creds so I cannot see that there would be a permissions issue at this point:
Error returned from attempting to run the script:
Successful connection ExchangeOnline using the same creds
I don't really know where to begin with troubleshooting this one.
Any ideas would be greatly appreciated.