The website was migrated from J 3.10 to latest J4.
The Floox template, Page Builder Pro and Helix 3 were also updated.
The website's contact form created through SP Page Builder is giving an error '0 Class 'JDispatcher' not found' when the contact form has the Google ReCaptcha enabled.
For some reason the ReCaptcha module displayed is the older version and not the current version, as you can see from this screenshot:
https://freeimage.host/i/HYonuSt
I got the form to work by enabling the Invisible ReCaptcha plugin in Joomla and selecting that on the contact form.