Hi @tamika77034 ,
In case you need us to help you with an issue while using our plugin, kindly create a new support thread instead of giving a bad rate to get our attention.
The issue of tip not being added to the total or the fatal error indicates an external conflict with something on your site, possibly a plugin or the theme.
We checked and confirmed that this issue didn’t occur within our plugin. On our dev site and live demo, we only use a pure installation of WooCommerce, WPCstore theme and our WPC plugin.
You can also check on your own that tip can be added properly: https://demo.wpclever.net/wpcot/cart/?add-to-cart=23
Again, we should emphasize that it is not an error o bug inherent in our plugin to be fixed. This is triggered by the combination of our plugin with another plugin or theme on your site.
If you are using any dynamic pricing/discount rules/block cart widget or block-based theme, this can be an issue. These prevents the tips from working properly and the conflict is irresolvable.
You can also test to confim my statement by deactivating all other plugins, only keep WooCommerce and our Order Tip plugin. Check the functionality you will see. Then reactivate others one by one to find the source of the conflict.