Problems with burning dvd's

This is my first post so hope it makes sense to someone. I have a mac. I am using Iskysoft dvd copy and 4media copy for mac. i am having problems with both of them. Sometimes they work fine, but other times I get error messages I just don’t understand. the first one is no effective dvd video, please change source. that one is when i use 4 media copy. the one with Isky soft is possible sector error. Isky tell me to put in a d9 dvd I do that but my dvd player will not play it. I check the dvd player which is a sony blue ray player and it should play. Some of my movies will not copy using 4 media copy, so I copy them using isky then burn them using 4 media, but they will play about 2 minutes and that is it. Sorry I guess I need a lot of help. Can anyone help? Thanks
I am using maxell dvd+r, office depot dvd-rw and memorex dvd+r dl disc’s.

Burn slower and trash the memowrecks DL media.