Same data, different tree

I am building a tree of my own data, but i can not get the same tree every time. i want to know the reasons. Did other people meet this problem?

Tree building often uses stochastic heuristics. Unless you set the random number generator seed of the tree builder, the output will be stochastic.

Thanks! Appreciatively!
So, how can i get a right tree? If i haven’t set the random number generator seed, is the tree wrong? Now, i have download some sequences of enterovirus and i follow the zika tutorial to build a tree without setting any parameters. i don’t know whether the tree is right.

Another problem i meet is that my prototype is excluded when i run the “augur refine”. I don’t know the reasons.