Getting empty page under All Campaigns >> Account Settings >> API (Apple Search Ads)

I am following the guideline at

https://developer.apple.com/documentation/apple_search_ads/implementing_oauth_for_the_apple_search_ads_api#3733114

However, I am getting an empty page like this :

I do not find a way upload my public key. Can someone help? Thanks.

Any solution?

Getting empty page under All Campaigns >> Account Settings >> API (Apple Search Ads)
 
 
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