I cannot log in to our wp-admin

We wanted to secure our website and so we installed a wordpress plugin (wp security). The next time I logged in, I could not do so in the admin page. We do not have an SSL certificate installed in the account. This error comes out.

Secure Connection Failed

An error occurred during a connection to www.metatrader.co.nz

SSL received a record that exceeded the maximum permissible length.

(Error code: ssl_error_rx_record_too_long)

The page you are trying to view can not be shown because the authenticity of the received data could not be verified.
Please contact the web site owners to inform them of this problem. Alternatively, use the command found in the help menu to report this broken site.

Pls help on how to resolve this issue.

Thanks in advance