The Portal (2014)

A dimension-traveling wizard gets stuck in the 21st century because cell-phone radiation interferes with his magic. With his home world on the brink of war, he seeks help from a jaded travel agent who he mistakes for a great sorceress. Without his powers to prove his identity, she has trouble taking him seriously, but finally agrees to reveal the secrets of our world in exchange for a lunch date.

Unfortunately the movie The Portal is not yet available on HBO Max.