      default_error_messages = {
          'invalid': _('Datetime has wrong format. Use one of these formats instead: {format}.'),
          'date': _('Expected a datetime but got a date.'),
      }
      datetime_parser = datetime.datetime.strptime
  
      def __init__(self, format=empty, input_formats=None, default_timezone=None, *args, **kwargs):
          if format is not empty:
              self.format = format
 
</s> remove         '2017-03-12T02:30:00': [
            'Datetime can not be converted to server timezone due to NonExistentTimeError.'],
        '2017-11-05T01:30:00': [
            'Datetime can not be converted to server timezone due to AmbiguousTimeError.']
 </s> add         '2017-03-12T02:30:00': ['Datetime can not be represented in timezone "America/New_York".'],
        '2017-11-05T01:30:00': ['Datetime can not be represented in timezone "America/New_York".'] </s> remove             return timezone.make_aware(value, field_timezone)
 </s> add             try:
                return timezone.make_aware(value, field_timezone)
            except Exception:
                self.fail('make_aware', timezone=field_timezone) </s> remove from django.utils.timezone import utc, pytz
 </s> add from django.utils.timezone import pytz, utc
        'make_aware': _('Datetime can not be represented in timezone "{timezone}".')
      default_error_messages = {
          'invalid': _('Datetime has wrong format. Use one of these formats instead: {format}.'),
          'date': _('Expected a datetime but got a date.'),
        'make_aware': _('Datetime can not be represented in timezone "{timezone}".')
      }
      datetime_parser = datetime.datetime.strptime
  
      def __init__(self, format=empty, input_formats=None, default_timezone=None, *args, **kwargs):
          if format is not empty:
              self.format = format
keep keep add keep keep keep keep keep keep
 Fix bug for not existent or ambiguous datetime during native to aware conversion in timezone with DST.
Ref: #4986 
rest_framework/fields.py