Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]: Prevalidating CN and SNI list for non-canonical-redirect-1 / ec-prime256v1         
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]: Traceback (most recent call last):                                                 
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/bin/acme-chief-backend", line 11, in <module>                         
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     load_entry_point('acme-chief==0.19', 'console_scripts', 'acme-chief-backend')()
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_chief.py", line 860, in main
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     ACMEChief().run()                                                              
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_chief.py", line 358, in run 
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     self.certificate_management()                                                  
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_chief.py", line 831, in certi
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     new_status = self._new_certificate(cert_id, key_type_id)                       
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_chief.py", line 496, in _new_
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     if cert_details['prevalidate'] and not self._prevalidate(cert_id, key_type_id):
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_chief.py", line 466, in _prev
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     if not pre_validator.validate(cert_details['CN']):                             
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_requests.py", line 527, in va
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     ret &= validator(name)                                                         
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:   File "/usr/lib/python3/dist-packages/acme_chief/acme_requests.py", line 588, in _v
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]:     if ns_record not in self.valid_ns_servers:                                     
Jul 19 18:13:04 deployment-acme-chief04 acme-chief-backend[15385]: TypeError: argument of type 'NoneType' is not iterable