You’re using old theme version. Please update.
Don’t forget to make backup site before updating.
Here is video tutorial how to update theme: https://www.youtube.com/watch?v=KdWESIIPU1k
The video tutorial is for Legenda theme, but the process is identical.
please navigate to Dashboard > Woocommerce > Settings > Products > Display > ‘Add to cart behaviour’ and enable ‘Redirect to the cart page after successful addition’ checkbox.
After that navigate to Theme options > ‘Single product page’ and disable Ajax ‘Add to cart’