Safari cannot open because of too many redirects

"Too many redirects" is the result of a self-referencing link (a page that loads another page that eventually loops around to the page that originally loaded another page) (see • below though) and the cause is usually a poorly implemented advertisement on that page. Only the website developer or the developer of those embedded advertisements can fix it with certainty, but you can attempt to terminate that endless loop by following If Safari isn't loading websites or quits on your iPhone, iPad, or iPod touch - Apple Support. "Clear website data" describes the steps most likely to work.

• There is no mandated limit to the number of redirects a website can implement, but there is a finite number generally considered acceptable. That number may be eight, or a dozen, but at some point Safari decides it's too many and tells you so.

Confirm that you followed all the steps described in If Safari isn't loading websites or quits on your iPhone, iPad, or iPod touch - Apple Support. Assuming you did, what was the website developer's response?

App is no help either.

I am not certain which app you are referring to. Is it Safari's Help menu? It won't have much to offer on that particular subject, but this is a relevant reply to an identical question a while ago:

Too Many Redirects...Safari Problem? - Apple Community

Ultimately, Safari only does what the remote server tells it to - if page A says redirect to page B, and page B says redirect to page A, then it's not exactly Safari's fault.

As I wrote Safari will only follow such self-referencing instructions so many times before it gives up. Only the website developer can fix that.