Hello Les,

Please check the setp 5 during export and put the URL with HTTPS.

Into your source code the export seems not correct

Axel

A full Https is mandatory for all payments solutions

Ive fixed this issue... but still get the error. Any other possible issues to deal with ?

Hello,
unfortunately when inspecting the page no additional details about the error are displayed during checkout.
I would suggest contacting your hosting provider to investigate.
What PHP version are you currently using on the server?

Eric

See attrached details 

Thanks ... Ive chosen the correct php version on the server & the issue is now resolved

Hello,

To help other users, which PHP version has fixed your issue ?

Axel

If everything is OK, don't forget to close your ticket.