Pro Header Builder Preview not showing

Hi there,

so despite having two Pro Licences, I have only just finally started to play with the header builder.
However I am getting nowhere, as when I am in the builder, and EDITING an assigned header, the preview of the header does not show the header.
The header shows on live site if I view any page outside of the builder, but does not show in the builder preview, so I cannot see how/what effect any changes I am making are having - so I cannot learn how to best use the builder.
I have the same issue with both sites using Pro.
Can you please check my installation and advise a solution. Test dev url sent in hidden details.
Many thanks
O.

Hello There,

Thanks for writing in! We have tried to log in and we failed. Every time we log in we got an Error 403.

Could you please guide us how can we log in so that we can finally resolve this issue?

Thank you in advance.

Thanks for the reply, that is very strange. I have just logged in again using the details i sent you.
I have set up another admin, and details to follow in secure note.

Hi There,

I Could login with the FIRST credentials give.

The header builder worked normally.

I am on Chrome PC.

Which specific header are facing issues, which browser and device you are using?

Thanks

Thanks Joao,

I have managed to get it working on a different Mac, with a newer version of Firefox (54.0.1).

The version on my Mac is 48.0.2, which does not work.
Not an issue, I can upgrade, and all is fine. Good to know though.

Thanks.

Thanks for letting us know!

Cheers!