As the attorneys at MARA's annual conference always remind us, to stay out of trouble, read the statutes and follow them to the letter. Here is a link to 23 MRS section 3101, which spells out what is required for calling a meeting: https://legislature.maine.gov/legis/statutes/23/title23sec3101.html
In particular, note paragraphs 2 and 3. After the initial meeting, it's no longer necessary to have the meeting called by a Notary. However, I believe the other requirements still apply - that is, there should be "written notice setting forth the time, place and purpose of the meeting. Copies of the warrant or similar written notice must be mailed by means of the United States Postal Service to the owners of all the parcels benefited by the private road, private way or bridge at the addresses set forth in the municipal tax records at least 30 days before the date of the meeting. The notice must inform the owners of the planned meeting's agenda and specify all items to be voted on, including, but not limited to, all proposed budget items or amendments that will determine the amount of money to be paid by each owner pursuant to subsection 5. Subsequent meetings may be called in the same manner or by a commissioner or board appointed at a previous meeting pursuant to subsection 5. "
Also, under paragraph 3, "E-mail may be used as an alternative to United States mail for sending notices and other materials under this section with the agreement of the receiving party as long as the communication includes the current address and telephone number of the sender for purposes of verification."