Missing Intermediate CA

Hi,

I have a FortiADC and a https website.

I have imported a certificate and key into local certificate, and an intermediate certificate in IntermediateCA as well.

It seems work well with browser. But when I use tool like SSL Checker to check the website, it still say that missing intermediate certificate.

I don't know which step I have missed or do it wrong.

Please help me to fix this issue.

Thanks,