My certificate is build like this:
ROOT CA (CN=AddTrust External CA Root) -> INTERMEDIATE CA (CN=COMODO RSA Certification Authority) -> INTERMEDIATE CA (CN=COMODO RSA Domain Validation Secure Server CA) -> MY-CPPM-SERVER-CERT (CN=COMODO RSA Domain Validation Secure Server CA)
All the other devices such Androids, Windows 8.1/10, MacOS trust the certificate and the problems seems to be only with iOS devices.
Has anybody else got similar experiences with this? Your feedback is appreciated !