When adding a mix to autodj, sometimes I like to rename it once uploaded to server, but when played on app it sometimes comes up with original name that I uploaded it with? Why does this happen?
Thanks.

You should make sure to change the ID3 tags as well, if they exist, not just the file's name. And after doing this, you need to also purge and update the Media Library (Media -> Options -> Purge library and update)

Ok, I'll give that a try thanks.
But this is my second server and didn't have to do any of that on first server, it just worked straight away.