I had same problem on the front page. Turns out database: mdl_course.maxbytes was set to '0'.
This will set the "Front Page" course id 1 to 500MB
UPDATE `mdl_course`SET`maxbytes`='52428800' WHERE `mdl_course`.`id`=1;
Warning this will reset all courses to 500MB
UPDATE `mdl_course`SET`maxbytes`='52428800'