Your intervocal β sound is a little too soft.
Your lips should not touch each other, which I believe you're doing, but they can't be too far apart. Say 'b', touching your lips together. Then part the lips slightly and say a 'b' sound. A 'b', with slightly parted lips, is the β sound in Spanish, used when the 'b' or 'v' consonant falls between vowels.
Listen
here.