Zend certified PHP/Magento developer

Which log file to check to find out why Check-out is not loading on mobile phones?

Magento 2.4.2-p1
Smartwave Porto theme
13 extensions from Amasty

We have the Amasty’s One Step Checkout but we don’t use it (it’s disabled but the Amasty One Step Checkout base is still intaleld). Everything used to work for customers ordering on mobile devices but now, when you click on ‘Go To Checkout’ on a smart phone, it loads:

Estimated Total
$12.34

up top and then just shows the spinning wheel which never goes away…

Is there a log file (or anything else) I could check in order to try to figure out what might be causing this?


UPDATED:

I have the following in debug.log:

[2023-01-11 21:10:49] main.WARNING: Broken reference: The element with the "sidebar.additional" ID wasn't found. Verify the ID and try again. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'catalog.compare.sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sale.reorder.sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'wishlist_sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sw.sidenav' element cannot be added as child to 'sidebar.main', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sidebar_second_block' element cannot be added as child to 'sidebar.second', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'product_view_custom_block' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'currency' tries to reorder itself towards 'store_language', but their parents are different: 'header.panel' and 'porto_header' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'catalog.compare.link' tries to reorder itself towards 'top.links', but their parents are different: 'header.links' and 'header.panel' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'yotpo_bottomline' tries to reorder itself towards 'product.info.addto', but their parents are different: 'product.info.main' and 'product.info.social' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sw.sidenav' tries to reorder itself towards 'category_leftnav', but their parents are different: 'sidebar.main' and '' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sidebar_second_block' tries to reorder itself towards '', but their parents are different: 'sidebar.second' and '' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'skip_gallery_before' tries to reorder itself towards 'product.info.media.image', but their parents are different: 'skip_gallery_before.wrapper' and 'product.info.media' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'skip_gallery_after' tries to reorder itself towards 'product.info.media.image', but their parents are different: 'skip_gallery_after.wrapper' and 'product.info.media' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'amasty.rewards.highlight.container' tries to reorder itself towards 'product.info.form.content', but their parents are different: 'alert.urls' and 'product.info' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'product_view_custom_block' tries to reorder itself towards '', but their parents are different: 'sidebar.additional' and '' respectively. [] []
[2023-01-11 21:10:53] main.WARNING: Broken reference: The element with the "sidebar.additional" ID wasn't found. Verify the ID and try again. [] []

The same can be found in system.log:

[2023-01-11 21:10:49] main.WARNING: Broken reference: The element with the "sidebar.additional" ID wasn't found. Verify the ID and try again. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'catalog.compare.sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sale.reorder.sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'wishlist_sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sw.sidenav' element cannot be added as child to 'sidebar.main', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sidebar_second_block' element cannot be added as child to 'sidebar.second', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'product_view_custom_block' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'currency' tries to reorder itself towards 'store_language', but their parents are different: 'header.panel' and 'porto_header' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'catalog.compare.link' tries to reorder itself towards 'top.links', but their parents are different: 'header.links' and 'header.panel' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'yotpo_bottomline' tries to reorder itself towards 'product.info.addto', but their parents are different: 'product.info.main' and 'product.info.social' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sw.sidenav' tries to reorder itself towards 'category_leftnav', but their parents are different: 'sidebar.main' and '' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'sidebar_second_block' tries to reorder itself towards '', but their parents are different: 'sidebar.second' and '' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'skip_gallery_before' tries to reorder itself towards 'product.info.media.image', but their parents are different: 'skip_gallery_before.wrapper' and 'product.info.media' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'skip_gallery_after' tries to reorder itself towards 'product.info.media.image', but their parents are different: 'skip_gallery_after.wrapper' and 'product.info.media' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'amasty.rewards.highlight.container' tries to reorder itself towards 'product.info.form.content', but their parents are different: 'alert.urls' and 'product.info' respectively. [] []
[2023-01-11 21:10:53] main.INFO: Broken reference: the 'product_view_custom_block' tries to reorder itself towards '', but their parents are different: 'sidebar.additional' and '' respectively. [] []
[2023-01-11 21:10:53] main.WARNING: Broken reference: The element with the "sidebar.additional" ID wasn't found. Verify the ID and try again. [] []