Thousands of KC customers were without their landline phones after problems with one of the exchanges.
Homes and businesses across east and north Hull were affected by the problem this afternoon for about two hours.
An investigation is looking into whether thunderstorms could be to blame.
A spokesman for KC said: "We experienced a problem this afternoon in one of our exchanges which meant that a large number of customers lost telephone service.
"We've now resolved the problem and we're sorry for any inconvenience this caused to the customers affected."
Homes and businesses across east and north Hull were affected by the problem this afternoon for about two hours.
An investigation is looking into whether thunderstorms could be to blame.
A spokesman for KC said: "We experienced a problem this afternoon in one of our exchanges which meant that a large number of customers lost telephone service.
"We've now resolved the problem and we're sorry for any inconvenience this caused to the customers affected."