Try to go to your wordpress dashboard → settings → Permalinks Settings and on the common settings press on post name and click on save
That might fix it
To fix the first error go to your cpanel → wp-content → plugins → download-attachments and open download-attachments.php file
In the line 106 you will find a code start with “privite” just change it to “public” and the problem will be solved
Hope that would help
I think you use WooCommerce add-on for LearnPress.
To fix this issue go to learnbress → Settings → Payments → WooCommerce Payment → Purchase Button And select Add to cart button and click on save