bathroom shower drain smells bad after running the shower?

[lizard]

after someone takes a shower the drain smells really bad, it smells fine when it's dry

someone takes a shower in there at least once a day

the drain isn't clogged

I poured diluted bleach down the drain several times, I poured hot water several times, and I put baking soda and vinegar down the drain also several times, it seemed to help for a bit but the smell comes right back

now what should I do?

thanks!