Hi I have a huge problem on my Mac and pc with after effects!!!

when I’m working with my after effects doing my visualizer doing ev righ. However, when I’m done with it and I want to preview before exporting it the song loses tempo and out of tune. in addition, sometimes it doesn’t produce the whole song just ia segemebt or the duration. Well I try to exported like that using render “queue” (don’t know how to spe that word)  ok so after saving it and waiting to export it seems going well, but the wait time is like 30 minuets to render. Anyway after waiting like some mi it says it failed because an Error of rendering!!! So how can I fix that i need help ? Hope someone will help me. Meanwhile I’m using motion 5 lol. I need this program for music purpose. Trying to add some effects to my songs. It is boring watching a listening a nice song but just a picture by itsel. Thank you hope this will help someone else who is having the same probleM.