Login action failed, with empty ‘data’ array

Dear Wprus developer,

I am sorry to report that I am experiencing a problem synchronizing login state across a couple of sites. I believe I have read all the relevant threads on this forum, and gone through every item in the FAQ. I have taken to testing the issue on a couple of newly-installed, vanilla test instances, and the problem is still occurring on my server. Here is a bit of information about environment and steps I took:
– Installed two instances of WordPress 5.7, with default English/US locale, running on Nginx, MariaDB and PHP 7.4, with TLS enabled. Both instances are publicly accessible.
– Installed Wprus v1.2.7 as the only active plugin.
– Took care to create remote site entries properly in both instances, checked every action except ‘create’ in one of the two directions (incoming on the first instance, outgoing on the second one), and double-checked encryption and signature keys.
– Set permalinks structure to ‘Post name’.
– Hit every ‘test’ button on both sites and got a successful result.
– Enabled logging.
– Created a test user on site A. This new user account is correctly replicated to site B.
– Logged in with test user on site A. Login state is not synchronized to site B. Log entries on site A seem normal (Login action, renewing token for site B, Added <URL> async URL in admin_footer. Log entries on site B are as follows:

2021-03-23 21:21:41 - Info - Token created: site https://siteb.tld/ - action "Login"
2021-03-23 21:21:43 - Success - Access granted
2021-03-23 21:21:43 - Alert - Login action failed - received invalid data.

		Array
(
    [data] => 
)
	

2021-03-23 21:21:43 - Alert - Login action failed - incoming login action not enabled for

This seems so blatant a problem (a full empty data structure) that I would guess it is in fact a benign issue. Yet I have not been able to troubleshoot this on my own. I hope you might be able to help or point me in the right direction. Meanwhile I will keep looking into it.

• This topic was modified 5 years ago by Lucas. Reason: formatting