Button on website stopped working & Need help fixing this bug

We have a WordPress installation with some custom code built on top. The custom code is a survey campaign system that sends out survey questions to users. On the campaign creation page you choose some settings and then press a "create" button to start the campaign. We were doing a bunch of updates to the features of the system and the create button stopped working in all browsers. When you press it nothing happens. In the browser console when press the button you get this error that might be related: (version numbers and some sensitive if remove for public posting) [login to view URL] [login to view URL] 500 (Internal Server Error) send @ [login to view URL] ajax @ [login to view URL] (anonymous) @ ?id= e @ [login to view URL] dispatch @ [login to view URL] [login to view URL] @ [login to view URL] Getting these apache errors in the error log PHP Warning: fopen(/home/***/public_html/wp-content/uploads/learndash/[login to view URL]): failed to open stream: Permission denied in /home/***/public_html/wp-content/plugins/learndash-memberpress/includes/[login to view URL] on line 64, referer: [login to view URL]**** [Sun Nov 10 16:06:39.343568 2019] [:error] [pid 6736] date_convert, referer: [login to view URL] [Sun Nov 10 16:06:39.343618 2019] [:error] [pid 6736] UTC, referer: [login to view URL] [Sun Nov 10 16:06:39.343631 2019] [:error] [pid 6736] validate_timezone, referer: [login to view URL] [Sun Nov 10 16:06:39.343640 2019] [:error] [pid 6736] America/Danmarkshavn, referer: [login to view URL] [Sun Nov 10 16:06:39.343665 2019] [:error] [pid 6736] Africa/Abidjan, referer: [login to view URL] [Sun Nov 10 16:06:39.343678 2019] [:error] [pid 6736] Africa/Abidjan, referer: [login to view URL] [Sun Nov 10 16:06:39.343694 2019] [:error] [pid 6736] validate_timezone, referer: [login to view URL] [Sun Nov 10 16:06:39.343717 2019] [:error] [pid 6736] America/Danmarkshavn, referer: [login to view URL] [Sun Nov 10 16:06:39.343753 2019] [:error] [pid 6736] Africa/Abidjan, referer: [login to view URL] [Sun Nov 10 16:06:39.344022 2019] [:error] [pid 6736] validate_timezone, referer: [login to view URL] [Sun Nov 10 16:06:39.344044 2019] [:error] [pid 6736] , referer: [login to view URL] [Sun Nov 10 16:06:39.344499 2019] [:error] [pid 6736] date_convert2, referer: [login to view URL] **IMPORTANT** Please post the word "Switchback" in the description of your bid response to show you read our project description read and not just an automated response. We usually delete automated bids that show up too fast and those that haven't read the description. Looking for someone to help fix today if possible and can start now. Thanks,