I exported the certificate presented by google.com and its has chaining as “GTS Root R1” -> “GTS CA 1C3” -> “*.google.com”. I put “GTS CA 1C3 + *.google.com” in inter.cer file. Then from chrome manage certificates I found “GTS Root R1” and exported it to root_ca.cer. Verifiied inter.cer with root_ca.cer and it was fine:-