Being blocked from connecting with current tenant

I've found a houseshare as a lodger, to move in to in a few weeks time. The tenant whose room I will take is female, the other two tenants are male. As a female myself, I thought it would be useful to chat to current female tenant about her experience living there. I asked for my number to be passed on to her, and have been told "sorry this is not possible". No further explanation. My intuition is telling me to walk away. That this is a red flag. I will question why this isn't possible of course - but would like to hear from others if I am being unreasonable or if this is indeed a red flag.