I've realized that Landing Page Publish is slow. So, While I was looking for solve method this issue, I found that can be improve Cloud Page in Dropbox using %%=TreatAsContent(HTTPGet('')=%% Method.

But, For some reason, that does not working what I thought.

TreatAsContent Method shows the HTML Language Source, Not the page to which the code is applied in Dropbox.

Could you tell me what I missed and How can I solve this problem?

Firstly, I Created Landing Page Using AMPScript.

and, Click the Specific link In Email, Move to the HTML Source Page in Dropbox.