Have already tried... I managed to get a little bit further: I switched off all the models in PEMFC and then started to switch them on one by one. So I discovered that it converges, however as soon as Liquid Phase ob, this error comes out...So does anyone have suggestions? I mean I checked my mesh and geometry several times. Also if it had smth to do with Boundary conditions, then it would be more like floating point and some other error, but not like shutting down of the whole fluent... but Ivan not very experienced, so probably there is smth I don’t know Thanks in advance!