I created my account today and while doing so I encountered a problem after receiving the approval mail.
After receiving my password i got the following error:
4100000 plugin_exception: plugin exception
Account: steem bandwidth limit exceeded. Please wait to transact or power up STEEM.
No matter how often I tried, I was not able to finish the process.
After a while of research I found out that the Steemit account, that creates the new account, exceeded the bandwith limit - not my own account (how? it was not created yet). Therefore: WAIT a while and try it again, there is nothing you can do about it besides waiting. About an hour later I tried again and it worked :)
Had this happen to me about 5 times in a row. Finally worked later. Don't forget to get the last generated password.
Same happened over here. Ended up having to go back into the email and click the link generating a new key. Did it about 3 times over the span of an hour before it worked. As modulatia mentioned don't forget to write down your key!