If you have ERR_TOO_MANY_REDIRECTS
/ "The page isn't redirecting properly" in Firefox,
but your network console doesn't show any obvious loops,
and your site includes HSTS / HTTP-Strict-Transport-Security
headers;
Then you may have an https://
request that contains an Location: http://
response,
which Firefox will occasionally refuse to upgrade to https://
.
Update the redirect destination to https://
and see if that solves your problems.