literally cannot speak when i answer the phone at work

literally cannot speak when i answer the phone at work this has been a serious problem for the past few months. i've always stuttered but lately i cannot even start my usual greeting when answering the phone. if i am able to, i have to wait in silence for like 10 seconds before speaking bc of the speech block. it's so fucking embarrassing and i've tried everything. i've tried to breathe, relax, not think about it as much, but it just won't fucking happen. when i pretend to answer the phone to practice i have no issue, but when it comes to the actual process of the phone ringing, pressing the answer button, and greeting, my brain just locks up