35 Miss. Code. R. 1-01-213
"Mail," "mailed," or "mailing" means placing a document or item in First Class United States Mail, postage prepaid, addressed to the person to whom the document or item is to be delivered at the last known address of that person. Where a person is represented by a representative in an administrative appeal before a hearing officer or the Review Board, the terms "mail," "mailed," or "mailing" shall also mean placing the document or item referred to in First Class United States Mail, postage prepaid, to the last known address of that person's representative. Mailing to the representative of a taxpayer, permittee, IFTA licensee, IRP registrant, tag holder, or title interest holder shall constitute mailing and notice to the taxpayer, permittee, IFTA licensee, IRP registrant, tag holder, or title interest holder.
35 Miss. Code. R. 1-01-213