Using Moodle 1.9.7
When using the certificate activity and choosing email notification to teacher this error appears:
ERROR: Could not instantiate mail function. ERROR: Could not instantiate mail function. ERROR: Could not instantiate mail function. ERROR: Could not instantiate mail function. FPDF error: Some data has already been output, can't send PDF file
Does the site email other notifications without issue? If so I suggest turning debugging up and see what error you are generating.
No it doesn't.
The the issue is with your email setting not certificate. You have to get the site emailing in general. I have a vague recollection of seeing the same error if a teacher is set to no mail too.
No - It was a moodle bug which they have recently fixed.
Can you tell me what the bug was that fixed the problem?. I am getting a FPDF error as well, and I cannot easily upgrade my moodle site. I am getting the error if I set the cert to be emailed, or displayed in a new window. My system is emailing other notification without issue.