After trying to register I receive 500 error.
There is a site (I do not know whether it is possible to insert links to other sites), I was allowed to modify it. Until Sunday, everything was ready and the customer decided to do a reset security token. After that registration ceased to work, it sends data to salesforce. In the console I see this error:
jquery.js? ver = 1.12.4: 4 POST http://somesite.com/wp-admin/admin-ajax.php 500 (Internal Server Error)
I also checked the old version of the project on the local machine, where the registration was working exactly.