It sounds like you managed to solve this problem but has someone pointed out to you that you can only record aprox. 12 minutes at a time on a Canon unless you use Magic Lantern software, then I’m not sure how long you can record. So that’s why I don’t normally recommend Canon DSLRs to record long speeches. What you have to do is to stop recording and then a second or so later start recording a new clip – if you time it right it can be OK, like during a laugh break or other interruption.
I hope this helps you in the future