Please check your pages through the W3c.org who is in charge of standards and practices and future for web browsers and web page code.

If follow standards and practices your web page will render properly in any browser and when the get updated.

For https://0t.gs/i1ABJc HTML https://validator.w3.org/ Errors https://validator.w3.org/check?uri=https%3A%2F%2F0t.gs%2Fi1ABJc&charset=%28detect+automatically%29&doctype=Inline&group=0

CSS https://jigsaw.w3.org/css-validator/ Errors None

What is up with that last line of code ? Why the // before the end tag ? Should that only be one instead of 2 It is 2 long to copy. but is this // a mistake ? /fz84I7OYIBtQP//CzAAw2NRAXr2Jr4AAAAASUVORK5CYII="/>

Am not following with what you have said. Web page redirects to place holder got that...so what is the index page ? Is this the first page the index ? Then would help your self to call it that. The Place Holder then will no longer by there. All Web sites main page is called index. That place holder page is up on the server. Delete your cache.

As for going to your app......what does the app do, why is Your Hosts file in the root of the domain should be looked at

Best I can do with that.. Correct your code. Try again

Please let us know if this solved your issue or if need further assistance.

Our web app is a plain redirect app

A) https://0t.gs/i1ABJc will 302 redirect to a url A, B) https://0t.gs/1sEPEO will 302 redirect to url B.

And a invalid token url which our cannot recognize say: C) https://0t.gs/123456 will go to https://0t.gs/placeholder

But in our case, all A,B and C goes to https://0t.gs/placeholder only on firefox, however works fine on any other browser.

We guess that Firefox has cached https://0t.gs/placeholder for any token url https://0t.gs/345433

Problem similar to this post https://support.mozilla.org/en-US/questions/981864

Ok, I got logged out and my total answers never got sent.

Use proper approved standards for redirect do the code as was suggested in Validator

On your 1st url A

Seamonkey gets redirected to Placeholder Internet Explorer gets redirected to Placeholder Edge goes to Russia and that is just plain mean hiding your address behind a redirect. Google will hate you.

Since other Browsers get redirected as well then this has nothing to do with Firefox and still remains a coding issue and misuse of redirection and would go further. but

You will have to fix this. Not a Mozilla Firefox Support Issue