OpenVpn Android: failed to parse certificates

I have a config file that works in windows, but when I try to use this file in the OpenVpn Android application, I get an error that says that it is not possible to parse the files ca.crt, cer.crt, cer.key and ta.key. I have the config file and all the other files in the same folder. My config files is this: ca ca.crt cer cer.crt key cer.key tls-auth ta.key 1 I have alse too to embedded the files in the config file, how it is explained in the documentation: https://openvpn.net/faq/i-am-having-trouble-importing-my-ovpn-file/ But I still get the same error. How I have set the certificates in the config file to can import it in the OpenVpn Android application? Thanks.