The 'warning' flag locked the daemon, and this flag will be still there for some time; Some are mining on the wrong chain, and not all the daemons are updated. And mining is not so easy with the current situation: the daemon goes in 'safe mode'. Anyway transferring to an exchange is not safe for the time being.
You cant.. exchganges are all locked down. And will remain so untill the developers say which one is right. With a working explorer, @ least the competent ones.