Q.Wisteria
I planted my wisteria 5 years ago. The 1st 3 years it blossomed beautifully. Last year and this year it produced copious buds, but they have failed to flower.

Here is some articles that will help you - one discusses the possible reasons wisteria buds do not open and the other why wisterias do not bloom:
https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-buds-dont-open.htm
https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-blooming-problems.htm