From someone who has had to file 8833 every year, here is some mailing advice:
Mail to Austin regardless of where in the U.S. you are, and do so using a courier service (UPS, FedEx, DHL, etc) NOT USPS. The physical mailing address is:
Austin - Internal Revenue Submission Processing Center
3651 S IH35,
Austin TX 78741
FWIW, I followed TurboTax/IRS mailing suggestions based on state of residence twice and both times it was a disaster...months and months without any news, a "missing return" yet the cheque was cashed by the IRS, etc. I had to get the Taxpayer Advocate involved one year. My advocate was the one who recommended in the future to send any return with an international component by courier to Austin, and ever since, my return has constantly been processed in a matter of weeks, even during COVID-19.
