Try submitting NY Form 2104-1 to your employer, declaring that you are a non-resident of NY and that you expect that 0% of your services will be performed within New York State. Here's a link to the form:
https://www.tax.ny.gov/pdf/current_forms/it/it2104_1_fill_in.pdf
The obvious purpose of this form is to guide employers to withhold (or not withhold) according to New York law.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
