How can I owe a delinquent motor vehicle tax bill when I was able to re-register a vehicle through CT DMV?

Re-registration through the Connecticut DMV is NOT a valid bill dispute. Being able to register or re-register a vehicle through the Connecticut DMV is NOT proof of payment of a bill or a waiver of the municipality’s right to collect a delinquent tax. There could be many reasons the DMV did not block your registration, such as your name differs slightly (use of a middle initial, married or maiden name, etc.) on the record, or there is some other data error. If the DMV data is incorrect, you are responsible for contacting the DMV and fixing any errors.