Hi FreePBX Community.
Posting this here in answer to the below issue as I cannot find anyone else that has solved it. Hope that it will help some other users. I tried the fix on the linked blog article and it worked first time for me, seems the handset is very fussy about its dial string compared to some others.
I found this fix in this blog article.
Hopefully it will help others with the same problem.
Sean
As you only just wrote the page you referenced, why couldn’t you have provided the information in this forum, instead. Moreover, I struggled to read your page, which badly fails on success criterion 1.4.3 of the Web Content Accessibility Guidelines (colour contrast), whereas whilst the FreePBX page does fail (e.g on the top banner), it passes on the important editorial content.
I thought it was just my old(er) eyes. At first I thought that I had to click on a pop-up so the linked page contents were less obfuscated. 