Baby girl suddenly terrified of men

Is this a phase that will pass? She's been in the company of my male family members from her very first week so she is very familiar with them, not so much with my husbands side. However these last few weeks she cries if aam, even a neighbour says hello to her! She cries if my dad or brother try to hold her or if my husbands father talks to her! What is this suddenly about, I've read it can be a phase but she's my first so I just wanted some advice please