Add to cart not working

[Onlinead]

Help needed please

Joomla 4.4.2
VirtueMart 4.2.4 10922
www.nanogencypru.eu

Upgrated from Joomla 3.10.x  where the system work fine. On Joomla 4.4.2 the add to card button doesn't work. It only shows loading while in  console shows 500 Internal server error.  If I disable the Display modal popup upon "Add to cart" it shows 0 Class 'JRequest' not found.
I have used different templates but with the same results.

Thanks in advance

[Jumbo!]

Uninstall any incompatible third-party extensions that are generating errors on your Joomla 4 site.

[Onlinead]

Only Joomla, Virtuemart and Akeeba is installed.  Nothing change though.  It looks  like there is a Joomla 4 compatibility issue.