If Confluence page contains a ":" (colon) in the tittle, the feature to "Export to PDF" will not work properly, Confluence will experience an Internal Server error.

Steps to Reproduce

1. Create a page
2. Insert a colon in the tittle
3. Go to Tools (Right side of the page)
4. Export to PDF

Here's a screenshot of a page containing the specific character:

Here's the error being reproduced after the PDF Export with Google Chrome browser:

Resolution

Remove the specific character ':' from the title of the pages that were having the error.