Page templates have a left variant and a right variant. You’ve only put your text frame on the left variant of the page, and the actual page within your project is a right page.
Edit the Page Template again - you’ll find that at the top of the Page Templates Editor there’s an L->R button that will copy everything from the left variant to the right.
(Though in this case, where your page number frames are tiny little boxes rather than spanning the whole width of the page, you’ll either need to not use the L->R button or correct the page number frame afterwards.)