Beep boop, I’m a bot! I dug through the forum to get you started. I sometimes get things wrong though, so do with this what you will until a human has a look.
This is expected on free hosting, and there’s nothing for anyone to fix on the server. The certificate chain is served without the intermediate certificate, and installing intermediates isn’t supported on free accounts. It’s only available on premium hosting. Your certificate itself is fine.
Browsers fetch the missing intermediate on their own, which is why Google and normal visitors verify the site without trouble. SSL checkers and programmatic clients like curl in Termux are stricter, so they report “unable to get local issuer certificate”. Our article on this says it only affects testing tools and programmatic access, not your visitors:
If you need curl to work without errors, you’d have to use premium hosting. Otherwise there’s nothing to change, so you can leave the certificate as it is.