Issuer: 

    ...
    Subject: CN=08:00:27:6B:52:F3-08-00-27-25-34-89

The issuer is completely empty.

... VERIFY ERROR: depth=1, could not extract X509 subject string from certificate

It looks like OpenVPN does not like an empty issuer.

To ensure issuer has some value, fill the values of country code, state, city, common name, organization name, organization unit name & email asked during creation of the certificate.

    Issuer: 

    ...
    Subject: CN=08:00:27:6B:52:F3-08-00-27-25-34-89

The issuer is completely empty.

... VERIFY ERROR: depth=1, could not extract X509 subject string from certificate

It looks like OpenVPN cannot deal with an empty issuer.

This is not unexpected since an empty issuer does not make much sense. Thus, whoever created the CA certificate should make sure that the subject of the CA certificate (and thus the issuer of the issued certificate) has a subject which describes the issuer instead of just leaving all the fields (common name, ...) empty.

    Issuer: 

    ...
    Subject: CN=08:00:27:6B:52:F3-08-00-27-25-34-89

The issuer is completely empty.

... VERIFY ERROR: depth=1, could not extract X509 subject string from certificate

It looks like OpenVPN does not like an empty issuer.

    Issuer: 

    ...
    Subject: CN=08:00:27:6B:52:F3-08-00-27-25-34-89

The issuer is completely empty.

... VERIFY ERROR: depth=1, could not extract X509 subject string from certificate

It looks like OpenVPN does not like an empty issuer.

To ensure issuer has some value, fill the values of country code, state, city, common name, organization name, organization unit name & email asked during creation of the certificate.