How do I upload a CA Chain?

I had just recently gotten an SSL Certificate, and it’s trusted in all browsers I’ve tested except Firefox because it was the only browser unable to get the CA Chain (even though it is installed in the browser). Because of this, I’d like to also upload the CA Chain to my SSL Certificate, though when I try through the cPanel, I either get the error “This certificate is NOT for your domain”, or “This certificate is in pem format/requires intermediates, this is not supported on free hosting”. Is there a way to upload it with no errors, that way I also get trusted in Firefox?

-None of the articles I checked helped, and neither did the support forums.

No, you cannot upload CA chains on free hosting. You need to upgrade your account to be able to upload the CA chain as well.

Oh, okay. Well, since I can’t upload the CA Chain, are there any other ways to get the Comodo SSL Certificate trusted by Firefox?

@TristianK3604 said:
Oh, okay. Well, since I can’t upload the CA Chain, are there any other ways to get the Comodo SSL Certificate trusted by Firefox?

Switch to a different operating system? Your Comodo certificate was accepted just fine by Firefox on my computer (running Ubuntu 16.04).

@Admin said:

@TristianK3604 said:
Oh, okay. Well, since I can’t upload the CA Chain, are there any other ways to get the Comodo SSL Certificate trusted by Firefox?

Switch to a different operating system? Your Comodo certificate was accepted just fine by Firefox on my computer (running Ubuntu 16.04).

Well, it has been about a day, so I guess that’s long enough for it to settle into firefox too.

It still shows up as untrusted on mine.

@TristianK3604 said:
It still shows up as untrusted on mine.

I’m not completely sure whether Firefox ships it’s own SSL verification method or whether it relies on the SSL chains of the operating system it’s installed on. If it’s the latter, that might explain the different behavior, especially if you’re using an older operating system.

Let’s see: Firefox uses it’s own certificate storage, I checked using Android 6.0.1, my device’s certificate storage has Comodo in it, and so does Firefox, and Firefox doesn’t trust Yahoo either, so it’s probably a problem with Firefox on my device.