It's impossible to tell what the reason is without knowing exactly what you eat etc. but the most common reason for no weight loss is so-called 'under-reporting' on food, mainly due to portion sizes being a lot smaller than you would think. For example cheese- the actual serving size is like a small box of matches or smaller, most people would have more than this as a portion. Protein servings are the size of a pack of cards- again smaller than most of us expect. Some foods- rice, potatoes and pasta in particular- can soon clock up extra calories as once again you guessed it- the serving size is small, and on MFP some foods are listed with smaller than normal portion sizes for some foods, no doubt to allow for those who wish to cut back, things like oven chips often have 100g portions listed when the packet serving is twice that. If you think that may be the reason, I recommend getting some digital kitchen scales, it's so quick and easy to simply weigh out the right amount and then you can keep much more accurate records.
If it's not portion sizes then I am not sure, drinking more water helps a lot, cutting down on sodium will help you to stop storing too much water weight... Just keep at it, I'm sure it will start moving.