Certificate file may not be valid

I’m using Certify SSL/TLS Certificate Manager
I have automated the SSL installation, request new certificate 60 days.

When the Certify app tried to request and install the certificate, I got the following error

An error occurred installing the certificate. Certificate file may not be valid: C:\ProgramData\Certify\certes\assets\pfx\xxxxxxxxxxxxxxxxxxxxx.pfx

My web server is (include version): IIS 10.0.14

The operating system my web server runs on is (include version): Windows Server 2016

It keeps happening for more websites, not just this one. But when I manually tried to install, it worked.

Can you let me know what is going on and how to get it working without this issue!