Are you using now the nn.Sequential wrapper for your classifier?
It looks like you’ve saved your model using layers fc1 and fc2 while these layers are now wrapped in nn.Sequential.
If so, you could try to use an OrderedDict to set the layer names again:
self.classifier = nn.Sequential(OrderedDict([
          ('fc1', nn.Linear(...)),
          ('relu1', nn.ReLU()),
          ('fc2', nn.Linear(...)),
          ('relu2', nn.ReLU())
]))