[SOLVED] Checkout cannot get past billing details .. (using Google reCaptcha)

OC 3.0.4.0
theme DEFAULT
Was adding paypal/gpay/ipay module and setting it up and configuring shipping.
Then I noticed I cannot get past Billing Details (guest or register account options)(step 2 on checkout) the continue button breifly 'activates' but nothing happens....

BUT.... if I use the paypal/gpay button instead of guest or register account, it goes straight through like its supposed to.....
I removed and checked all my geo settings and postage settings, reverting back to 'as install default' and still nothing....
(note, I have multi-domain shop, other shop I have not yet set up, but has same issue, eventually, I want domain 1 with 'free shipping' and domain 2 with calculated shipping, but thats a later issue )

anyone think of anything to check out?

Check both the OpenCart and PHP error logs. Check your web browser's developer console. Try with the default theme.

What exact payment extension are you talking about? And why haven't you contacted the extension author?

"Check both the OpenCart and PHP error logs. Check your web browser's developer console. Try with the default theme."
nothing appearing on logs, and as per orig post, i am on default theme.

"What exact payment extension are you talking about? And why haven't you contacted the extension author?"
its PayPal Checkout Integration
and, i uninstalled said extension, and issue is still there...... sooooooooooo

FIXED IT

it was not the theme, nor the payment module.

IT was the google capcha settings!
UNDER system-settings-default go to option and scroll down to Captcha options, and make sure that register and guest checkout are not ticked. For it must be doing a captcha check somewhere but without input its not doing anything