Propane line clog

Degraded/missing thermal bushing in ACME can cause propane container valve to not open, ie no flow. the excess flow feature limits flow, it does not stop flow.

The entire assembly is relatively cheap... it is likely more expensive to buy the bubble stuff to check for leaks than the gas tape and the replacement hose and ACME fitting.

What makes you think it is clogged? It has a check valve in the green knob end.

Those hoses do collapse over time and should be replaced if very old.

Just buy new......

Inside that Green Nut is an 'excess flow' check valve (ball bearing that floats in mid/center position when pressure is equal....low pressure downstream ball is moved to closed position by higher pressure upstream minimizing flow)

Internals of Green Nut get clogged up......throw away. Get new.

The ACME fitting includes a check valve that may be corroded. Since the whole hose assembly is only a $10 item, it may not be worth spending much time on it.