WTF am I doing wrong

Weigh and track all my food, 500 calorie intake deficit, solid meal/macro plan, plenty of hydration, good sleep, walk 4-5x a week for an hour a clip, and yet the results have been flat for 6 weeks. I lost a couple pounds at the beginning, and now a month and a half straight at the same weight.

For the men out there, what calorie intake level are you at. Is 1700 still too high? I weigh 258, 6 ft, office job.

Trying to figure out what I'm doing wrong. Cert. Nutritionist says I'm right where I should be and should be losing at least 1.5 lb a week.