checkout continue button stuck on loading

I have just realised that each time a user resgistered withink checkout and presses the contiune button the user is not taken to the next step

however if the user refreshes the page they are sent to the next step

i have checked the error logs and all i see is

PHP Notice: Undefined index: customer_group in /var/www/vhosts/blinds4value.co.uk/httpdocs/vqmod/vqcache/vq2-catalog_model_account_customer.php on line 28

does anyone have any ideas i have disabled all extensions but still no joy

Perhaps also clear the vqcache as well as disabling the extensions.

HI i have done this to all possible solutions

You use a JOURNAL Theme/Extension. Did you check on this Matter by use of your DEFAULT Theme already,
and without any Extensions active, like Journal Caching, or other Journal Theme related Options, by use of
the OC DEFAULT Checkout Routine ?
Ernie

Hi i have done both suggestions already to eliminate any of the extensions of effecting the process the default theme has the same problem also just gets stuck on loading as you can see the loading icon next to the button and thats it nothing happens after that