How is your Port connected to the Teac? The line in on the Port should be, I suspect, connected to a line level output on the Teac. It sounds like you already have the line out on the Port connected to one of the line ins on the Teac. Most people use a standard tape loop for both. 

Since you’ve done this before, you’ll be aware that the line in on the Port will have the 75ms delay, so there will be a slight delay between your Sonos speakers and the speakers connected to the Teac, when playing something on your Teac…but in sync when you’re streaming from your Sonos. 

As a test can you substitute another analog source for the CD players?

If you post a picture of the back of the TEAC, or post which amp it is, users here could point you to what connection to use.

Hi all- quick update:

I have my setup working with 1 of the cd players so I know the problem is not with the port (line in or out). I’ll now focus on the connection between the 2 disc players as that is no doubt the issue. 

The Teac amp back is below. The model is Teac stereo receiver AG H-300, as set up with the single cd player plugged in and working. 
 

I suggest that you immediately power down the TEAC and neaten the speaker wire connections. There is too much stray wire. I don’t know why you have not had an issue with this.

Apart from the connection between the two CD players you are having trouble with, since the TEAC amp has a “tape loop” (called CD-R/MD) I’d suggest to connect the “out” on the Port to “PLAY” on the CD-R/MD section of the TEAC and the “in” on the Port to the “REC”. This way you can play from the Port to the amp and from the amp to the Port (and thus other Sonos speakers.

You could equally use the one labeled ‘TAPE’. Either one works. 

I am getting sound out from whichever disc player is  cabled and configure as disc player 2, but still no luck getting the daisy chain feature to play through the port- it doesn’t matter which machine is designated #1, only #2 will work. In other words, I’ve checked each machine individually ;as well as the port). The issue seems to be that although the signal from disc player 1 shows up in the Sonos app (dancing soundbars- which suggests the signal is getting to the port), it does not play back through the amp or speakers… (in theory it should if the signal gets to the port, especially when using the tape loop). 

I’m beginning to wonder if there is something odd about the amp…
 

Unfortunately, the bouncing bars, in the Sonos interface, only reflect the fact that there is an input connected. I don’t believe there is any relationship between music actually playing, and those bars bouncing. 

I’m not familiar with a CD ‘pass through/daisy chain’ feature, you may need to contact Sony about that. I can’t quite figure out what the clipped manual page is telling me, if it isn’t audio out on the one CD player to CD in on the other, then audio out on that other to line in on the receiver. But we’re getting in to Sony territory there, and I’m no expert on Sony, I worked for a non-music division of Sony. Both CD players would need to be powered on for that to work, I’d think.

If it were me, I’d probably connect the Sonos Port to the Tape RCA jacks, and the two CD players to the two other ‘inputs’ on the Teac, and avoid daisy chaining completely.

Shoot, to be honest, I’d actually copy the CDs to my NAS, using a music ripper software package, and then use the Sonos music player to access them, rather than relying on a clunky CD changer. I’d have better access to randomized tracks, and a lot fewer ‘clunks’ while the machine is changing CDs. 

I second the rip the CDs to a NAS, it is far less aggravation.

Oops. Missed the fact there’s a real tape loop. Of course you can use that too,