Adext AI needs to write to (or edit) your ad account in order to copy your ad group/set and to manage demographic budgets for your ads on your behalf.
Typical reasons this might occur:
Your ad account does not have the proper write/edit privileges
Please verify that you can edit the ad group/set that you selected in Adext AI. If all seems well there, then please send us a message through the chat icon at the lower right of your screen and we will research and attempt to solve why this is happening in your specific case.