Updating products, when I try to change Variations, e.g. “Create variations from all attributes”, the system goes into a never-ending wait. All products.

NB. Internet speed is OK and no problems with anything else.

I am also having a problem when after updating a product, instead of returning to the product, there is only a blank screen, and I have to reload the page.

I am updating the website via the Avada theme and WooCommerce.

I have been in touch with Avada Support and they advise:

“I do see there is a 500 error in the Ajax, Screenshot here —> http://i.imgur.com/4YEP77G.png

The admin ajax error shows on the default theme of WordPress too, Video here —–> https://www.dropbox.com/s/q0de06vgkrg2u3a/2017-08-28_20-12-13.mp4?dl=0

It appears there is an issue with the admin ajax.”

I have no idea about ajax, so any help would be appreciated.

Thank you.

The page I need help with: [log in to see the link]