Cannot Dynamically Set Source or Target Points for Beam Particle Effects

I faced the same confusion, so for anyone coming to this question:
In Particle Emitter Settings:
Beam Data>Beam>Beam Method must be set to Target
Target>Target Method must be set to “User Set” (Don’t confuse with Target>Target>TargetTangent Method)

Blueprint:
Set Beam Target Point with a New Target Point Location