Error when validating CA Certificate

Following instructions on page 30 for “Create and validate the CA certificate” and receive an error during step 6 for AnywhereUSB 2 device.

openssl verify -CAfile cacert.crt server.crt

error 18 at 0 depth lookup: self signed certificate
error server.crt: verification failed

How can I validate without receiving error 18? Am I missing something?