Siri stops & starts working again on my iPhone X

Why does Siri stop working on my iPhone X then start working again even though the option for it to be used has always stayed on & I’ve always had cellular data access on the iPhone, I’ve tried force restarting it but that didn’t resolve the issue but then it would start working again for no particular reason & it has now stopped working again, I’m very annoyed with this issue that I’m having & would greatly appreciate a solution if someone knows how to resolve this issue that I’m continuing to have? Thanks if you can provide a solution, Tim