"Send Request" button in the Request Approval screen is unresponsive post-migration
After a space is migrated from server to cloud, request approval made in any pages cannot be completed because the Send Request button is unclickable, and is constantly spinning.
This issue is caused because one of the page’s has a page restriction within the space prior to the migration.
Confluence apps are unable to access restricted content through REST API. More information on this can be found here.
Remove any page restrictions on the space level.
Go to Space Tools > Permissions > Restricted Pages.
Remove all the restricted pages and migrate the space to cloud again.
The Send Request button will work as expected.