I cannot really confirm as I have not filed yet... but when I first edited my rental income as being owned by a SMLLC there was a message that said good news, this year if you have 1 SMLCC then form 568 can be electronically filed. So I was very happy to see that. Then I subsequently got to the situation where the return couldn't be filed at all due the error message in this thread. The last smart check no longer shows that error for my return. In prior years, the filing instructions at the front of the CA return made it very clear it had to be mailed. There is a section called Other Forms to Mail and my 2018 instructions indicated to mail form 568. I suggest you look at page 1 of the filing instructions on the CA return.
