Answer by daoliker for Tensorflow: Cannot interpret feed_dict key as Tensor

Variable x is not in the same graph as model, try to define all of these in the same graph scope. For example,

# define a graph
graph1 = tf.Graph()
with graph1.as_default():
    # placeholder
    x = tf.placeholder(...)
    y = tf.placeholder(...)
    # create model
    model = create(x, w, b)

with tf.Session(graph=graph1) as sess:
# initialize all the variables
sess.run(init)
# then feed_dict
# ......