Is the mmpool server located in the US or Europe?
Don't worry about location. In the past I've found blocks for mmpool via both US as well as Europe orders.
I created a mining order on nicehash and it keeps dying saying "pool difficulty too low".
Same problem here. Nicehash frequently change the starting and/or working difficulty, therefore:
@mmpool, is there a chance we get a parameter "initial difficulty" or similar? We need a solution for a reliable nh compatibility. On the other hand we don't want to exclude the small miners and hardware owners who need lower Difficulty values.
Alternatively, see philipma1957's idea (2 mining addresses).