12-180-12 Me. Code R. § 6
A prohibited practice complaint may not be filed with the Board until the complaining party has served a copy of the complaint upon the party against whom the charge is made. As provided in Chapter 10, § 8, service will be considered complete on the date that service was provided to the other party by email, so long as service by mail, hand delivery or delivery via a delivery service occurred on the same calendar day.
The executive director may at any time require the complainant to file proof of the date that the complaint was served on the respondent if proof of service is not filed with the complaint. Failure to provide the proof of service as required by the executive director is grounds for dismissal of the complaint. Proof of service may be in the form of either a certified mail receipt signed by the recipient addressee or an agent of the addressee, a signed and dated acknowledgment of receipt by hand delivery, a dated confirmation of delivery from the Post Office or other delivery service, a dated statement of refusal of service or a copy of the sent email that includes the date and the email address to which it was sent. These requirements also apply to amended complaints.
12-180 C.M.R. ch. 12, § 6