Getting an empty PDF attached to e-mail on staging/production server, but works fine when tested locally

[mdominguez]

Description
I get an empty PDF attached to e-mail on staging/production server, but works fine locally. When I try to download the PDF through the CMS, it downloads and shows fine. Any idea which steps I can take to debug or find the differences between local and server? Nothing in the logs related to this too unfortunately.. :/

Steps to reproduce

1. Create order and let the Gift voucher PDF be attached to the e-mail
2. Empty PDF on staging/production, but works fine when downloaded through the CMS or when tested via e-mail locally

Additional info

• Plugin version: 2.5.8
• Craft version: 3.6.11.1
• Multi-site: Yes

Additional context