A quick update as its been a while. TP Link R&D could not provide a solution, but sugguested changing the MTU. And also confirmed to return unit. Brought another unit from a well known manurfactor,...

@Col_H To All, The issue has been passed to R@D, hence I have asked for a full refund as the unit does not operate as per fuctionallity description. Also asked for supply chain to advised as others...

@Col_H TP Link have been workinhg on this for a couple of days now. What I question, it probally takes 1 hour to find a unit, say 1 hour to set up and 1 minute to see if it all works. Sadly like in...

@Clive_A Thank you, you acknowledged that it all points to the unit. As you stated it registers, all ok. Upon an outbound call it either rings the mobile once and goes engaged, or to a landline it...

@Clive_A Hi, I have passed this over to TP link Technical Support, as you are all correct. This issue is way above the normal fault finding requirements by the user. This is not a DIY home solution...

@Col_H Thanks for that, i did try and find an upgrade package but could not locate it. Anyway, carried out an upgrade and re-tried. Same result. Double checked via outbound calls by using another...