The BLU Vivo 5 is an Android smartphone produced by BLU, an American consumer electronics company. The 5 was produced through a partnership between BLU and Vivo Communication Technology Co. Ltd., a Chinese technology company. The BLU Vivo 5 was released in February 2016.
This most likely do to the headphone jack having dirt or lint in it. It causing the phone to think that headphones are plugged in. try to blow it out or use a small swap to clean with alcohol.