CHICAGO (WBBM) – If you subscribe to Comcast Internet service in the Chicago area, Northwest Indiana or southwest Michigan, you must have wondered where it went Sunday night.

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An outage of high-speed Internet started at 7:30 p.m. Sunday and finally ended at about 12:15 a.m. Monday.

Cause of the outage is still under investigation.

The outage inconvenienced anyone who wanted to check e-mail or book a flight and consternation for those who need Internet service to earn a living.

The company advises customers who experienced problems connecting to the internet, to turn off their modems and turn them back on to reset service.

During the outage, a recorded message at 1-800-Comcast said the company was experiencing technical difficulties, and asked customers to call back later. The company updated customers via its Twitter account @comcastcares.

The outage did not affect Comcast phone or cable television services.

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