deficient and the counterclaimant provided a second opportunity to amend it within 30 days. If the counterclaim is refiled and served again within the second 30-day period and is compliant, the counterclaimant and parties shall be so notified, but if the counterclaim still fails to comply, upon confirmation of its noncompliance by a Copyright Claims Officer, the counterclaim, but not the proceeding, shall be dismissed without prejudice. (3) Dismissal for good cause The Copyright Claims Board shall dismiss a proceeding without prejudice if, upon reviewing a claim or counterclaim, or at any other time in a proceeding, the Copyright Claims Board concludes that it is unsuitable for determination by the Copyright Claims Board, including due to the following: (A) The failure to join a necessary party. (B) The lack of an essential witness, evidence, or expert testimony. (C) Determination of a relevant issue of law or fact that could exceed the competence of the Copyright Claims Board. (g) Service of notice and claims To proceed with a claim against a respondent, a claimant must within 90 days of receiving notification to proceed with service file proof of service on the respondent with the Copyright Claims Board. To effectuate service on a respondent, the claimant must cause notice of the proceeding and a copy of the claim to be served on the respondent, either by personal service or pursuant to a waiver of personal service, as prescribed in regulations established by the Register of Copyrights. Such regulations shall include the following requirements and conditions: (1) The notice of the proceeding shall adhere to a prescribed form and shall set forth the nature of the Copyright Claims Board and proceeding, the respondent’s right to opt out, and the consequences of opting out and not opting out, including a prominent statement that, by not opting out within the 30-day period, the respondent— (A) will forgo the opportunity to have the dispute decided by a court created under article III of the Constitution of the