Existing certificates are now missing background image after change of server and upgrade of Moodle 3.3.6 to 3.8.
The correct images are still in the Custom Certificate template system and certificates show correctly in preview.
When students try to open their certificates they get just the name and date and no background image with the certificate details.
I've tried removing and replacing the certificate images and using new certificate images.
The course transfer was undertaken between an AWS EC2 Bitnami Moodle 3.3.6 instance and a newly built Moodle 3.8 on Ubuntu 18.04. The courses were simply backed up and restored.
Is it possible part of the certificate is pointing to a different url?
Looking at the customcert tables, there is a pointer to img src="@@PLUGINFILE@@....
Wondering of this is s the same location in the Bitnami and Ubuntu versions and if not, how to point this correctly?