Wont burn at x4 speed

Unable to to burn at x4 with nero

I have a pioneer dvd burner 106 and have had no problems with burning up until now.
I am bunring a movie on a x4 dvd-r disc at x4 speed. When nero starts the process, it stops after 1 minute and said burn prcess failed.
I return to do the same project at x2 speed and it works.
I have burnt atx4 on these disc’s before, why has this changed now?
Nero will only burn at x2 speed.

Then i try it on a dvd+rw and it sets the speed at x2.4 speed and doesnt allow the option to change the speed in the drop-box.

Please help me with this one fellas