Hello,
Thank you for reporting this error.
It looks like this error is related to BuddyBoss, since it has also been reported in the past for a completely different plugin (Event Tickets and Registration):
https://wordpress.org/support/topic/error-when-connecting-to-stripe-or-paypal/
The validation link is normally handled by a WP-REST API endpoint in the wallets plugin. It does not require you to be logged in or authenticated. The only requirement is that you are the bearer of the correct nonce.
For some reason, BuddyBoss doesn’t like other plugins using the WP-REST API.
This function removes all REST API endpoints, except for their own endpoings:
This is hooked to rest_request_before_callbacks. See here:
https://github.com/buddyboss/buddyboss-platform/blob/2.3.90/src/bp-core/bp-core-actions.php#L486
So basically the BuddyBoss plugin doesn’t seem to allow other plugins to use the WordPress REST API. Not very nice of them. Please tell them.
with regards