Am I doing something wrong with weight loss?

Let me get this straight: You dropped from 255 to 240 in two weeks, then the scale stalled for two weeks? You have a calorie goal of 2290 but eat more like 1600. You have a very active job 6 days a week, plus you're in the gym every day, walking on the treadmill.

Would I be correct in guessing that you asked for a weight loss rate of 2 pounds a week to get the 2290 goal? Are you eating back your exercise calories on top of your base calories, i.e., is it 1600ish plus exercise you're eating, or just straight 1600-ish? (If you made me guess, I'd guess you're not eating the exercise calories, given the overall pattern.)

You're completely normal. You made a dramatic change in your habits, lost a massive 7.5 pounds per week on average for two weeks. Some of that weight was fat, some was water, probably some was lean mass but we'll hope not much. It's normal for a bigger chunk of the scale weight at the start to be water weight.

When that happens, it's normal for the body to rebalance its water retention at some point. When it happens, that increase in retained water will mask fat loss progress for a while.

On top of that, you're very likely over-stressing your body, which may add even more water weight. As a mail carrier who spends time treadmilling (for 200 calories) every day and lifting (it's not clear whether that's every day or not, but if I had to guess, I'm thinking it's probably every day.

If the lifting and treadmill were new when you started trying to lose weight, realize that new exercise will add water weight for muscle repair.

As far as overstressing: Given your job and exercise schedule (very active!), it's likely that your calorie needs to maintain your current weight (240) could be 3500+ daily. Whatever you put in your MFP profile, if you told it you want to lose 2 pounds a week and got 2290 as a goal - MFP thinks it would take 3290 calories for you to maintain your 255 pound weight.

Your BMR (basal metabolic rate) - the amount you'd burn in a coma, flat on your back in bed - is likely around 2100-2200. You're eating around 1600, way less than your MFP goal, way way less than your probable daily calorie needs, and even way less than your BMR.

That's stress, and it's not good for you in a variety of ways. More relevant here, stress increases cortisol, and cortisol can increase water retention, adding to the scale confusion.

You may be hitting your macro percents, but if you eat too few calories, you may still not be getting adequate nutrition. There's no way to get adequate nutrition on too few calories: We need certain gram amounts of the macro nutrients, not just X, Y, and Z percents of some tiny number of calories. Low-balling that nutrition will increase the stress on your body.

What are you doing wrong? In my opinion, two things, only one of which you asked about.

The one you asked about: Your scale stall is about some kind of water weight weirdness. Patience is required. Water retention doesn't keep increasing and increasing. Eventually fat loss will outpace it, and the scale will drop again.

The one you didn't ask about: IMO, you're riding for a fall. You're under-eating dramatically, IMO. I under-ate accidentally at first when I joined MFP (because I'm an odd duck, and MFP underestimates my calorie needs). I felt great, motivated, not hungry . . . until I hit a wall. I got weak and fatigued. I corrected quickly, but it took weeks to regain normal strength and energy. No one needs that, especially not someone with a physically demanding job. I'm sure you're younger than I am, but I think this striving for ultra-fast loss will eventually catch up with you.

I was lucky. I maybe had only a little hair thinning (several weeks after the too-low calories, because that's usually a delayed effect). There can be immune system compromise, gallbladder problems, and more/worse. (Keep in mind that your heart is a muscle, and muscle loss is a risk in a very large deficit.)

Very fast weight loss can be a trap. It can be counter-productive. The health risks are one obvious thing. On top of that, fast loss often backfires at some point: Deprivation triggered overeating, breaks in the action, maybe giving up altogether.

IMO, you're in a high risk position. I'd suggest giving it a rethink. If your calorie goal is 2290, eat at least that. Assuming you followed MFP's instructions, if you set your activity level based on pre-exercise activity (job, home chores, etc.), you should also eat back a fair fraction of your exercise calories on top of that 2290.

Many of us here suggest losing no more than 0.5-1% of current body weight per week, unless severely obese and under close medical supervision for deficiencies or complications. You seem to be shooting for 3+ pounds a week, 1.25%+ of your current weight weekly. Another common rule of thumb is to cut no more than 20-25% of current TDEE (total daily energy expenditure, the total maintenance calories including exercise). Using the most conservative estimate, you're probably at roughly 1600 of 3290, a 53% deficit.

I'd suggest slowing down the bus, frankly. Most of the "pedal to the metal", lose-fast folks we see here don't stay here for long. Sincerely, it would be nice if that's because they succeed quickly, and bail because we're mean here about fast loss, like I'm being now. Unfortunately, I think it's more likely that they become part of the statistics saying that most diet attempts fail.

Please give it a rethink. I may be a stranger, but I want you to succeed. Losing from obese to a healthy weight (and staying there for nearly 8 years since, after 30 previous years of overweight/obesity) has been a huge quality of life improvement for me. I want everyone to have that improvement, and that includes you. No matter how you take this advice (or don't), that's absolutely where I'm coming from: Wanting you to succeed long term.

Best wishes!