Layer concatenate_1 was called with an input that isn't a symbolic tensor

problem

As mentioned in the title, when writing code, I encountered the problem of Layer concatenate_1 was called with an input that isn't a symbolic tensor. Check that the concatenate object is indeed the tensor object. Why is there such a problem?

Solution

Check whether the concatenate parameter is passed wrong in the code. Note that the parameter is placed in [], not ().

emb_all = layers.Concatenate(axis=-1)([emb, emb_1])
emb_all = layers.concatenate([emb, emb_1], axis=-1)