Hi @wwwnews!
This is usually due to a theme/plugin conflict.
As a first step, I would recommend you temporarily switch to a default theme, like Storefront, to see if the issue persists. If the issue goes away, then you’ll need to contact your theme author to resolve this.
If the issue is still there, then you’ll need to disable all your plugins, except for WooCommerce, to see if that resolves the issue.
You can read more about the conflict test here:
https://docs.woocommerce.com/document/how-to-test-for-conflicts/
If you’re not comfortable doing this on your production site, then you can use something like https://www.ads-software.com/plugins/wp-staging/ to create a staging site where you’d be able to run these tests without it impacting your production site.
Please let us know how that goes.