You've generated a new ad in Ads Manager but are unable to change the ad type. The section for ad type is grayed out, as shown below.
This is not an error or a bug but is instead expected behavior. Because changing the ad type requires different information from you, it's not possible to change the ad type at this stage (after the ad has been generated by PSAI).
Instead of changing the type, you can create a new ad by following the instructions below.
1. Delete or Save
Exit the current ad (the one of the type you don't want) by either saving it as a draft or deleting it.
2. Go Back to Ads Manager
Then navigate back to Ads Manager by clicking "View All Ads" at the top or by clicking "Manage" from the left-hand tool bar.
3. Create a New Ad
From your Ads Manager dashboard, generate a new ad in any way you prefer:
Since you won't be able to change it later, doublecheck that you're creating your preferred ad type whenever you start generating your ad.
If you are having trouble with the instructions above, the quickest way to get help is to contact PSAI Support. Fill out a Support ticket at this link, or start by opening the Help widget in the bottom right corner of the screen.