California Code, Unemployment Insurance Code - UIC § 2707.4

(a) The claimant may, within 30 days after the service of the notice of computation or recomputation, protest the accuracy of the computation or recomputation. The 30-day period may be extended for good cause. The department shall consider any such protest and shall promptly notify the claimant of the recomputation or denial of recomputation. The claimant may appeal from a notice of denial of recomputation in the manner prescribed in Section 2707.2. The director shall be an interested party to any appeal.

(b) “Good cause,” as used in this section, shall include, but not be limited to, mistake, inadvertence, surprise, or excusable neglect.

(c) This section shall become operative on March 1, 2018.