I'm having a problem that started, I believe, after I upgraded Joomla to version to 3.8.10. I'm using SEBLOD 3.15.0. The problem I'm having is with an Upload - Image type. Specifically, it's an image I'm using as the article header. It's worked perfectly in the past, but now, ever install is returning a "invalid file" error when I try to upload an image. I've checked the php.ini and the upload size is 64m. I've tried a few things, like upgrading SEBLOD to the latest version, but nothing is working. Is anyone else having this issue? I'm going to experiment a little more, but if anyone has already fixed this, I'd love to know how.
For the start check if you have file type listed in allowed extensions in both Joomla media manager options and Seblod options. Please note that e.g. JPG is not the same as jpg on unix systems, case matters.