I have no problem with different brands also. Gutterman's is the majority of my threads but I think when these little ones came into existance was Gutterman's even around? Coats and Clark and Double Duty I use also. Are you threading your needle the right way? That is always a problem and remember the needle flat side is to the left I believe not to the back like most machines. I would check these two areas also. Take a deep breath and rethread and reinsert the bobbin. Sometimes that works too. Hope you get it running right real soon.