Error: 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
I was facing weird issue, on customer tenant being a global admin when I try to enable the site collection level app catalog getting an error of :
"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"
Add-SPOSiteCollectionAppCatalog -Site <sitename>
In a documentation there is small note which helped me to resolve this issue:
"NOTE: The account used to execute these commands must be a Site Collection Administrator on both the tenant-level App Catalog and the target Site Collection."
To add the site collection level catalog, Although account has Global Administrator permission but if don't have site collection admin rights to the tenant level App Catalog, this will fail and lead to above error. Error message is unclear at this moment.
Hope you found this post useful!