I’m sorry for my late reply.
After removing logits_aux  as you advised, it worked!!!
I cannot thank you enough!
However, why it couldn’t convert with logits_aux??
cclass AuxiliaryHeadCIFAR(nn.Module):

  def __init__(self, C, num_classes):
    """assuming input size 8x8"""
    super(AuxiliaryHeadCIFAR, self).__init__()
    self.features = nn.Sequential(
      nn.ReLU(inplace=True),
      nn.AvgPool2d(5, stride=3, padding=0, count_include_pad=False), # image size = 2 x 2
      nn.Conv2d(C, 128, 1, bias=False),
      nn.BatchNorm2d(128),
      nn.ReLU(inplace=True),
      nn.Conv2d(128, 768, 2, bias=False),
      nn.BatchNorm2d(768),
      nn.ReLU(inplace=True)
    )
    self.classifier = nn.Linear(768, num_classes)

  def forward(self, x):
    x = self.features(x)
    x = self.classifier(x.view(x.size(0),-1))
    return x