Reasonable cause
(2) Reasonable cause defined. The penalty is waived for reasonable cause only if the filer establishes that either (i) There are significant mitigating factors with respect to the failure, as described in paragraph (b) of this section; or (ii) The failure arose from events beyond the filer's control (impediment), as described in paragraph (c) of this section. (iii) Moreover, the filer must establish that the filer acted in a responsible manner, as described in paragraph (d) of this section, both before and after the failure occurred. Thus, if the filer establishes that there are significant mitigating factors for a failure but is unable to establish that the filer acted in a responsible manner, the mitigating factors will not be sufficient to obtain a waiver of the penalty. Similarly, if the filer establishes that a failure arose from an impediment but is unable to establish that the filer acted in a responsible manner, the impediment will not be sufficient to obtain a waiver of the penalty. See paragraph (g) of this section for the reasonable cause safe harbor for persons who exercise due diligence. See paragraph (h) of this section for the reasonable cause safe harbor after an election under section 6722(c)(3)(B) and 301.6722-1(d)(3).