I'm getting this after installing the RssAggregator macro XAR and using it in a page:
 Failed to execute macro: groovy
 org.xwiki.rendering.macro.MacroExecutionException: You don't have the right to
execute this script
        at
org.xwiki.rendering.macro.script.AbstractJSR223ScriptMacro.execute(AbstractJSR223ScriptMacro.java:134)
        at
org.xwiki.rendering.macro.script.AbstractJSR223ScriptMacro.execute(AbstractJSR223ScriptMacro.java:50)
        at
org.xwiki.rendering.internal.transformation.MacroTransformation.transformOnce(MacroTransformation.java:175)
 etc...
  
Ideas?
Rick