It seems you can load the saved model, but what is not clear where is the variable classifier initialized before you use when loading:
state_dict = (checkpoint[‘state_dict’])
model = models.densenet121(pretrained = False)
model.load_state_dict(new_state_dict,strict=False)
model.fc = **classifier**
for parameter in model.parameters():
parameter.requires_grad = False
model.eval()

If the linear layer is not initialized/loaded with trained weights then the predictions will not be accurate.