The email should contain contact information to call our Customer Support line to verify your account. Once you have verified your identity, they will walk you through steps to release the hold on your taxes.
If you do not call, your taxes will be released and submitted to the IRS after 48 hours.
https://ttlc.intuit.com/questions/2930355-i-received-an-email-about-a-return-with-my-information-being-on-hold