Lost Android app access

Running latest version of app. Backend works well and is hosted by apache and php 7.2. I just installed php-fpm for apache since more websites will be hosted running different versions of php.

It seems that I lost access to the site from my Android app after that. Looking at the apache logs I see:
x.x.x.x - - [12/Apr/2021:03:20:14 +0200] “POST /tt-rss//api/ HTTP/1.1” 404 209 “-” “Tiny Tiny RSS (Android) 1.298 (532) Dalvik/2.1.0 (Linux; U; Android 9; Pixel 3a XL Build/xxx)”

I have x’ed out ip address and build but the app, and the log, both show a 404 error. The api subdirectory does contain an index. php file. I do note, however, that the POST command contains a double slash rather than the expected single slash - could that be the reason for the 404? If so, I am not sure what has happened.

This isn’t really an Apache httpd and/or PHP support forum, so you might have more luck elsewhere.