Hey, @haarbollen!
Thanks for confirming!
Another thing that can cause this error is conflict with the theme, plugins or custom code.
Can you please run a conflict test to see if the issue persists?
To test, you’ll first want to change the theme on your site to Storefront, then check to see if the issue is still present. If that resolves the issue, you’ll want to get in touch with your theme’s developer and see if they have an update or fix for you.
If changing the theme doesn’t help, you’ll want to deactivate all plugins except for WooCommerce and take a look(please note this includes deactivating page builders such as Elementor and code plugins such as Codesnipets). If that fixes the problem, re-enable the other plugins one by one (gradually), checking after each, to see where the issue is coming from.
— Be sure you have a good backup in place of your full site and database. You can ask your host for backup functionality or you can consider using a service like Jetpack. If something goes wrong, you will be able to restore it.
— Also, you can consider using a plugin like Health Check & Troubleshooting. This is a plugin developed by the WordPress community and it is helpful to disable plugins without affecting your current site visitors.
— It is important to consider as well a staging functionality in case you would not like to touch your production site (you can ask your host if they offer this service), or you can use WP Staging for quickly spinning up a new test site.
You can find more about this in this guide.
Please let us know about your findings.
Have a wonderful day!