What is the hash validation error in Woocommece?

Question

ROBOKASSA

Hello, I connected the robokassa payment gateway plugin: ( https://wordpress.org/plugins/wc-robokassa/ ), chose it as a payment method in woocommerce, set up the plugin and robokassa, test payments are made correctly, no errors occur, but when I try to make a real payment, the status of the order remains "Awaiting payment" and several notes appear:

The error remains with any hashing algorithm, it passes the test but does not pass the real one.
WP: 4.9.8, downgraded from 5.0.3 on purpose, but it didn't help.
wocommerce: 3.5.0, rolled back to 3.0.0, didn't help either.
What could be causing this error?

Answer 1

Check server time