"Forgot my password" link is not working

I am running multiple sites on a WordPress multisite install. For some reason, when users click on the Forgot My Password link on the log in page, they are sent the email to change their passwords, and then when they go to change the password, it doesn’t save the change – they just get an error that says “this key does not appear to be invalid.” this keeps happening repeatedly and they cannot change their passwords. I’ve attached a screenshot: Screenshot of error message This has happened to many users so I don’t think it’s user error. Has anyone seen this before?

Thanks!