Strange one this.
While checking & inflating the tyres i found i could not put any air into the front passenger side?
The valve pin was stuck solid, so i removed it and fitted another valve only to find that was the same?
In the end i had to over inflate the tyre and quickly fit the valve.
What could be stopping the valve from working properly?

Could it be that a tyre sealant has been used on it in the past?

Hmmm, maybe.