Thanks for the reporting.
Could you please share about which stage the error popped out?
Just from the error message, PowerApps seems to not be able to find the proper list, please first verify the list is available to access, make sure it is not deleted.
Besides, take a try with a newly created list, or creating an App from the SharePoint list directly, see if there would be errors:
The list has just been created and is therefore available for use. I am getting the error when I put the address of my team site on SharePoint and then choose the list and click create.
I took a look at your logs, and your SharePoint cannot find the list "SpecialistRequests". Hence the mssage "List Not Found" (although that would be a lot more useful if it included the actual name).