500 Internal Server Error after upgrade to 1.7.1

Support
1

Good day.
I just upgraded from 1.6.3 to 1.7.1 running php 8.1.
All is working well, until I want to mail an invoice, then I receive a 500 Internal Server Error.
Where do I start looking?
Thanks

2

The InvoicePlane log can be found in application/logs and hopefully the error can be found there.
First place to look would probably be the Invoice Template.

application/views/invoice_templates/pdf/

Start with the error in the log and continue from there