I have two domains, a.com and b.com, both with reCAPTCHA enabled. I’m using the same codebase for both websites, but the reCAPTCHA implementation works on a.com but not on b.com. Here’s the setup:

a.com: The reCAPTCHA keys were created by a friend 2 years ago. The keys are for reCAPTCHA v3, as the site uses grecaptcha.execute.

b.com: The reCAPTCHA keys were created today, and I used reCAPTCHA v3 for this domain as well.

On b.com, I get an error:

contact.php:37 Uncaught (in promise) TypeError: Cannot set properties of null (setting 'value')
    at contact.php:37:71
(anonymous) @   contact.php:37
Promise.then        
then    @   recaptcha__en.js:591
(anonymous) @   contact.php:36
Promise.then        
(anonymous) @   recaptcha__en.js:138
(anonymous) @   recaptcha__en.js:195
(anonymous) @   recaptcha__en.js:196
(anonymous) @   recaptcha__en.js:472
(anonymous) @   recaptcha__en.js:196
(anonymous) @   recaptcha__en.js:1132
(anonymous) @   recaptcha__en.js:1142

Here’s the client-side code I’m using:

Also I noticed that the reCAPTCHA tokens generated for the two domains have different lengths:

For a.com, the token is about 1100 characters.

For b.com, the token is around 2400 characters.

Can someone tell me what is wrong with this code?