Note the repositories section in

https://nexus.onap.org/content/repositories/releases/org/onap/aai/aai-common/aai-common/1.6.8/aai-common-1.6.8.pom

It points to:  http://repo2.maven.org/maven2/

repo2.maven.org  has been decomissioned.   

https://repo1.maven.org/maven2/     must be used instead.

In addition, the central repository, requires https access, so the new URL should use https.

It would be betterif it does not include any repositories section, in addition if possible should be upgraded to use latest oparent.

The oparent version used is fairly dated 2.1.0 so we pull some unsafe dependencies.