Registration for the 45,000 open slots in the race began Tuesday, but the website was overwhelmed by people logging on.
The Chicago Marathon is scheduled for October 13.
Wednesday statement from from Bank of America Chicago Marathon Executive Race Director Carey Pinkowski:
The Bank of America Chicago Marathon would like to thank all of our interested participants for their patience during registration. Registration for the 2013 Bank of America Chicago Marathon continues to be suspended as our registration provider Active.com works to resolve technical issues. Registration will not reopen this week. All updates will be provided on Facebook, our website and email. To be added to the registration announcement email, interested participants can sign up at www.chicagomarathon.com/registrationupdate