index.htm file not being recognised on newly uploaded site, but index.php is

I have uploaded an old static website to a new server. But the index.htm homepage is not being recognised. It opens, instead, an index.php file pre-existing in the web host's public_html folder, showing their default landing page.

Assuming the .php file was being prioritised, I deleted it, leaving just index.htm, but then I got a 403 'Forbidden...' page. So I then changed the index.htm file to index.php - and it worked!

I was also able to go to all the other .htm pages on the site, but I couldn't get back to the home page from any of those as, of course, all the links therein are pointing to index.htm not index.php.

I could change all the links but that would be tedious. Does anybody know why the web server is not recognising the initial index.htm file (but does recognise all the others!)?

And can I fix it without having to change all those links?

Thanks.

source https://stackoverflow.com/questions/77788620/index-htm-file-not-being-recognised-on-newly-uploaded-site-but-index-php-is