I signed up to the OJS mailing list with two different email addresses. When I try to unsubscribe using the information supplied from the *second* sign-up process, I get the following message: 

There was an error unsubscribing you. Please ensure your email address and password are correct.

I've ensured that both are correct, according to the subscription notification email I received. However, I *am* able to unsubscribe my first sign-up attempt using the information from that first notification email, and then subsequently unsubscribe my second attempt. 

I know it's probably not a normal situation for folks to sign up twice, but it's probably worth investigating as it may occasionally happen by mistake.