A loose RJ45 connector may be due to an insufficient bend in the connector retaining tab.  

To remedy this:

  1. Remove the RJ45 plug from the inline/splitter connector
  2. Retract the strain relief boot slightly and bend the retaining tab back by approximately 45 - 60 degrees
    Note. bending the tab further may result in damage)
  3. Return the strain relief boot to its original location over the retaining tab ensuring snag less operation and secure fitment

The following video gives a demonstration of this process