Beta 1 and 2 of Catalina was working just fine for me, updated to beta 3 and the SMB shares are no longer accessible- I can see the drive and or the shared folders listed but when attempting to open them I get the error message that an error occurred. I’ll try an non iOS13 Apple TV shortly but I think it’s having the same issues and was also just fine under the first 2 betas.
I have recreated the shares, not only shared the drive but also the folders and even created a sharing only user account on my iMac.
Dev’s, is this also broken for you? And yes, it’s a beta OS, I know the risks!