Doorbell only rings if I hold down the doorbell button

Thanks Captain11.  I spoke to support again and they say it won't work with a digital doorbell.   I had to ask how I could tell if my doorbell is digital and should have known the speaker would be strong indicator. Lol.

So I need to get a mechanical one but I now have another problem.  It doesn't seem to have a transformer or if it does it's buried in the wall or attic.

Do you know if a digital doorbell would have to have a transformer?

In over my head it seems 

@bjreed3​ Ah! Yes, the Video Doorbell Pro is not compatible with digital doorbells - it does need to be hooked up to a mechanical doorbell. Do you happen to know if your doorbell is wired or wireless? If your doorbell is wired, it should have a transformer that supplies it power.

@bjreed3​ I just came back to this thread, sorry for the delay. I see Emily responsed. My doorbell (mechanical chime) has transformer in the basement ceiling, in a drop panel ceiling so yes, I can get to it.  For yours, if you have a basement look there in the ceiling. No basement, check closets. If no luck, ask a neighbor who has the same model house. They may know.