steps to replicate.
have new interface on
create new page in pages app
try to select template
Post about the error https://knowledgebase.progress.com/articles/Article/bad-request-error-while-in-the-page-template-selection-when-creating-a-page-in-the-new-interface
I followed the instructions for the fix, including restarting the app and the error persists.
No error is logged in the error.txt file
it was this issue knowledgebase.progress.com/.../AdminApp-Creating-page-throws-error-on-the-page-template-selecting-step-and-shows-blank-template-selector