Hi guys,
In the past I have succesfully inserted a 'Click to Call' button, in both - html, and on main menus... and you can see this in action at the bottom of the home page in the contact us section
<a href="tel:1300935938"> - 1300 935 938 - </a>
OR on the MAIN MENU - add
Inside Link field just: tel:1300935938 
On this site, I have done what I normally do... by creating a URL menu link and added the phone number in the LINK FIELD... but its not working?
https://imgur.com/cnDN2Pv
Any suggestions why it's not working - located on the top right of the main menu?
https://www.messagingonhold.com.au
Also... I have a SITEMAP (OSMap) plugin installed, but the MENU link doesn't work for it either???
If you go into the plugins editor and click on the HTML button, you see the page, and I have selected the MAP in the MENU ITEM LINK... but the page does not come up??? 
https://imgur.com/a/h9OjML3
When you click on the Menu Tab... the URL changes it to:
https://www.messagingonhold.com.au/#undefined
Is there something wrong with my Main Menu???
Look forward to your reply.