Sign out of the app completely, then sign back in with the exact same email you used to purchase the plan, since a mismatched Adobe ID is a common cause of this.
Try to Restore Purchase, tap in the profile icon > Subscriptions > Restore Purchase, to relink your purchase to your account.
On Android, clear the app's cache under Settings > Apps > Acrobat > Storage > Clear cache, then reopen it.
On iOS, offload the app under Settings > General > iPhone Storage > Acrobat, then reinstall it from the App Store.
Let us know what you find, and we can pick up from there.