Certificate verification problem.

[amfergom]

Hello

I have created a Certificate using letsEncrypt and I have set the configurations on PEP-steelskin:
config.ssl = {
active: true,
keyFile: 'pathtocertificate/privkey1.pem',
certFile: 'pathtocertificate/cert1.pem'
}

In postman when I execute a postman script, it return "Could not get any response".
I have used the same certificate files in a web page and the certificate works very well.
¿Why does the same certificate work in apache2 but not works in PEP?

Thank you very much in advance.
Best regard.