you need to give permissions to the App Management Service Application and Microsoft SharePoint Foundation Subscription Settings Service Application

Select the App Management Service Application--> Permissions in the Ribbon add the user name

Select the Subscription Settings Service Application--> Permissions in the Ribbon add the user name

and now go to CA --> APPS --> Configure App URLs

that did the trick for me .....

you need to give permissions to the App Management Service Application and Microsoft SharePoint Foundation Subscription Settings Service Application

• Select the App Management Service Application

• Permissions in the Ribbon add the user name

• Select the Subscription Settings Service Application

• Permissions in the Ribbon add the user name

• and now go to CA

• APPS

• Configure App URLs

that did the trick for me .....