As nobody said that x must be a real number, the complete solution seems to be
and (no surprise) Mathcad/MuPad is not able to find that solution - at least not without much help
In fact, the symbolics is not even able to simplify a valid solution like x= -7pi+i*6pi completely
but at least it knows (when explicitly asked) the the expression simplifies to e^pi
Fazit (one more time): Mathcad is not the right tool for tasks like this!