Thank you for your answer.
Membership has been resolved by changing the default settings.

I'd like to ask you again about the update I asked you last time.

I applied it the first way, but it can't be solved. 
Is it because he used a child theme?

Can I apply only downloaded themes from Filezilla to this theme instead of child theme? Please explain in detail. I think it will help a lot.

2) Manual Update:
Install the installable file in downloads tab at ThemeForest.
Switch to a WordPress default theme and remove the old Bifrost.
Click on the top button Add New and insert the installable file.
Note: Make sure to delete the Neuron Core plugin and install it again from the new Bifrost, it should be on version 2.0.0 to have all the features and the elements of update.

Will the product or settings I put up before I proceed?

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Your theme (Bifrost Child ) contains an earlier copy of the WooCommerce template file. You may need to update this file to be compatible with the latest version of WooCommerce. Suggestions to resolve this issue:

Update the theme to the latest version. If there are no updates, contact the author of the theme for compatibility with the latest version of WooCommerce.
If you made changes by copying the template file, you must copy the new template version and reapply the changes.
Learn more about templates View affected templates

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Hi,

What I would suggest you first is to do a backup and you'll be able to do that via this plugin.

- https://wordpress.org/plugins/updraftplus/

Please go to this article, I've explained how you can update your theme. Just scroll at the bottom.

- https://neuronthemes.com/bifrost/whats-new-in-2-0/