Please see below for step by step guide on how to Test for Plugin and Theme Conflicts:
If you have a staging site, do everything on the staging site first. If you do not have one, you can reach out to your Host to create it. A staging site is a copy or clone of the Live site.
- Update WordPress to the latest, then your plugins and theme. You can do this under Dashboard > Updates.
- From there see if it is working. If not, then it might be a plugin or theme conflict.
- You can read more about plugin and theme conflicts here: https://docs.woocommerce.com/document/woocommerce-self-service-guide/
The best way to determine if the issue is being caused by a theme and/or plugin is to do the following:
- Temporarily switch your theme back to the Storefront or Twenty Seventeen Theme.
- Disable all plugins except for WooCommerce and Peach Payments
- Test to see if the issue has been resolved.
If that resolves the issue, then one-by-one you can switch back your theme and re-enable your plugins, testing in between, until you find the one causing the conflict/showing the error.
Again, this is best done on a staging site so the Live site is unaffected during this troubleshooting.
Please let us know the results or reach out to us on email@example.com should you require further assistance.