Woocommerce & Woo subscriptions issues with Updated WordPress

I have recently set up a subdomain to upgrade WordPress, Theme Avada and plugins, fix any issues and then transfer to main domain. I still have my main domain without the upgrades to WP and Avada theme, the plugins are updated.

I am using Woocommerce for programs/products and Woocommerce Subscriptions, both updated on main domain and working fine.

After upgrading WP and Avada theme with the upgraded Woocommerce and Subscriptions, the Subscriptions and/or Woocommerce are not working properly. In Woocommerce settings, the tabs for Checkout and Subscriptions are there but when clicked on are a blank grey page and in the front end the checkout pages do not show except for a white screen.

I reverted to an older version of Subscriptions and have the same issue. If I remove Subscriptions then Woocommerce shows the checkout tab page in backend and front end.

I have also increased memory to 254M thinking it was a memory issue but did not make a difference. Cleared cache just in case and nothing changed.

I thought it was a theme issue so reverted back to an older version of Avada theme, uploaded the newest version of Woocommerce and Subscriptions and have the same issue.

Next step was to revert to an older version of WordPress, updated version of Avada Theme and Woocommerce and Subscriptions and everything working fine.

So this tells me it is an incompatibility issue with the updated versions of WordPress, Woocommerce and Subscriptions. I am not the only one having this issue, I have read the same from others.

Can anyone help to solve this issue? I really need the “add to cart” and “checkout” to work properly. And I hate to use an older version of WordPress as it may not be as secure.

Thank you in advance! Jillian

Ps. I have not added a link to my subdomain since it is not live.

https://ww.wp.xz.cn/plugins/woocommerce/