Today when we tried to enable site collection app catalog using PowerShell we got the below error.
“Add- : Must have Manage Web Site permissions or be a tenant admin in order to add or remove sites from the site collection app catalog allow list”
Verified to check this issue:
I am having access to SharePoint Tenant admin but still I am facing this issue when I am trying to run the PowerShell.
After some time realized that we need access to SharePoint Appstore site collection admin access to that particular account you are running PowerShell .