Maryland State Government Section 10-209
§ 10-209.
  (a)   Where a licensing statute provides for service other than by regular mail, notice under this subtitle may be sent by regular mail to the address of record of a person holding a license issued by the agency if:
    (1)   the person is required by law to advise the agency of the address; and
    (2)   the agency has been unsuccessful in giving notice in the manner otherwise provided by the licensing statute.
  (b)   Upon a showing that the person neither knew nor had reasonable opportunity to know of the fact of service, a person served by regular mail under subsection (a) of this section shall be granted a hearing.
  (c)   A person holding a license shall be deemed to have had a reasonable opportunity to know of the fact of service if:
    (1)   the person is required by law to notify the agency of a change of address within a specified period of time;
    (2)   the person failed to notify the agency in accordance with the law;
    (3)   the agency or the Office mailed the notice to the address of record; and
    (4)   the agency did not have actual notice of the change of address prior to service.