The [In-Port/Out-Port] settings at "Device" may not be properly set. Open [Preferences] on the TRAKTOR menu, then click the [Controller Manager] tab.
1. At [Device], select [Pioneer.DJM-T1], then at [In-Port] select the device corresponding to the DJM-T1.
2. At [Device], select [Pioneer.DJM-T1 – Generic MIDI], then at [In-Port] and [Out-Port] select the audio device corresponding to the DJM-T1.