20 CFR § 404.911 - Good cause for missing the deadline to request review.
(a) In determining whether you have shown that you had good cause for missing a deadline to request review we consider -
(1) What circumstances kept you from making the request on time;
(2) Whether our action misled you;
(3) Whether you did not understand the requirements of the Act resulting from amendments to the Act, other legislation, or court decisions; and
(4) Whether you had any physical, mental, educational, or linguistic limitations (including any lack of facility with the English language) which prevented you from filing a timely request or from understanding or knowing about the need to file a timely request for review.
(b) Examples of circumstances where good cause may exist include, but are not limited to, the following situations:
(1) You were seriously ill and were prevented from contacting us in person, in writing, or through a friend, relative, or other person.
(2) There was a death or serious illness in your immediate family.
(3) Important records were destroyed or damaged by fire or other accidental cause.
(4) You were trying very hard to find necessary information to support your claim but did not find the information within the stated time periods.
(5) You asked us for additional information explaining our action within the time limit, and within 60 days of receiving the explanation you requested reconsideration or a hearing, or within 30 days of receiving the explanation you requested Appeal Council review or filed a civil suit.
(6) We gave you incorrect or incomplete information about when and how to request administrative review or to file a civil suit.
(7) You did not receive notice of the determination or decision.
(8) You sent the request to another Government agency in good faith within the time limit and the request did not reach us until after the time period had expired.
(9) Unusual or unavoidable circumstances exist, including the circumstances described in paragraph (a)(4) of this section, which show that you could not have known of the need to file timely, or which prevented you from filing timely.