Proximity Sensor not working after earpiece replacement

I recently replaced a non-functioning earpiece speaker. The repair went very well and I can hear now. But...since doing the repair it appears that the proximity sensor that blacks out the screen when talking on the phone at ear level no longer works. I keep ear switching to speaker or mute or hangup when trying to use the phone. Is there a fix for this or is there something I should go back in and check on that may have happened during the earpiece speaker repair process.

Thanks,

Bernie