Thank you for bringing this issue to the Help and Support Forum! Encountering disconnects during Champion Selection (especially in Ranked) can cause severe wait-time penalties placed on your account, such as the 30 minute wait time you stated. Hopefully we can resolve this issue to ensure it does not happen in the future.
First and foremost, there may be some confusion regarding what exactly a Maestro Error is. Maestro is a serviced used by League of Legends to confirm that a Player is maintaining a constant and stable connection to our Servers. It does this by sending a small packet of information back and forth (think of two people playing 'catch') between your computer and our Servers. If this connection is completely blocked, or severely delayed (imagine someone not getting the ball back, or the person throwing the ball in the complete wrong direction), then a Maestro Error is provided, and you are kicked from Champion Selection.
At this point, we need to determine why this small packet of information is being lost between your computer and our Servers. Typically this occurs when an over-zealous 3rd party program (such as a Firewall or Anti-virus) blocks this connection and packet of information being sent back and forth. Because of this, I strongly recommend that you review the following Knowledge Base Article which provides steps on how to ensure that these programs are properly configured for League of Legends:
Yet, if you are still encountering these Maestro Errors even after following all of the steps to this guide, then please do not hesitate to let us know by submitting a new Support Ticket*, so we may work with you one-on-one until arriving at a Full Resolution. If you do submit us a new ticket, make sure that you include the following information so we may investigate further:
1) Network Analysis: http://support.leagueoflegends.com/e...twork-analysis
2) NetworkInfo Log: http://support.leagueoflegends.com/e...etworkinfo-log
3) Process List: http://support.leagueoflegends.com/e...a-process-list
* Keep in mind that this advice was given based upon the information provided. If you would appreciate a further one-on-one interaction to solve this issue, make sure to send us a Support Ticket! You can send one from here: https://support.leagueoflegends.com/tickets/new Also, if you could please provide a link to this forum thread in the new ticket, it would be incredibly helpful!