See this TurboTax support FAQ for error code 603 - https://ttlc.intuit.com/community/tax-topics/help/error-code-603-all-the-available-activations-for-t...
Use this website to contact TurboTax support during business hours - https://support.turbotax.intuit.com/contact/
Or -
Support can also be reached by messaging them on these pages https://www.facebook.com/turbotax/ and https://twitter.com/TeamTurboTax
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Use this phone number and select TurboTax - 1-800-4-INTUIT (1-800-446-8848)
Or -
On every TurboTax web page, including this one, scroll down to the bottom of the page and click on Contact Us
