Must have a CPA?

[Tomoko Hale]

Many people mentioned that it is strongly recommended to have a CPA as a part of the team. 
I started looking in my area and am a beginner of real estate investment.
Would you please tell me the reasons to have CPA vs a tax accountant. What if a tax accountant has a lot of knowledge and experiences of tax laws including investment, would it matter?  
I had a call with an accounting firm this morning and he mentioned something like he is not a CPA so he is not able to represent like CPA.

What does it mean?

Thank you!