You do not need to “redefine” the repositories available using the helper methods in RepositoryHandler. Those repositories are only used if you call them. Instead, your repository setup should just include the configuration of the repositories that you do want to use.
mavenLocal() is adding the standard configuration to use your local maven repository.
maven { url "http://***/artifactory/libs/" } configures a maven format repository (this is all you need for your artifactory repository. Note this is not the same as mavenCentral()).
jcenter { url "http://***/artifactory/libs/" } is adding the standard configuration for the jcenter() repository. The closure is not reconfiguring it as you expect. You should remove this.