View PDF Error

When I want to view the product invoice in the orders, I get the error I added. I updated the plugin to the latest version and cleared the cache, but after a while I started getting the same error again. When I clear the cache, it works for a short time, but then it gives the same error again.
When I tried to export the settings in the plugin, it gave another error. When I cleared the cache, that error went away, but the export error also repeats. Can you solve the problem?
The plugin and theme were not updated before the error started to appear. This error suddenly appeared.