Hi,
For a better troubleshooting, I suggest you can do as the followings:
1. You can create a new page library to test if it works.
2. I suggest you can check the ULS log for detailed error message, it will be easier to figure out the issue. By default, the ULS log of SharePoint 2013 is located at the path:
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\LOGS
You can use ULS Viewer to see the detailed error message.
Here are some detailed articles for your reference:
https://sharepointlogviewer.codeplex.com/
https://ulsviewer.codeplex.com/
Thanks
Best Regards