I've had an issue with Spotify and detection of Chromecast on "Connect to a Device" specifically on my Google Pixel, for a number of months now. This only presents itself on Spotify, and when I go on another Chromecast enabled app on my Google Pixel, it casts no problem to my Chromecast, which is why I've narrowed it down to Spotify and it's integration with the Google Pixel (or Android in general?). This needs to be fixed. I have a workaround that currently works, but it's with my work phone or laptop, and is just inconvenient, and is certainly not the way Spotify Connect is meant to work.
Steps to Reproduce:
1. Log into Spotify app on Google Pixel phone. Assure that you are connected to the same network as the Chromecast.
2. Play any song, and go to the currently playing page.
3. Tap "Devices Available". NOTE: "Devices Available" doesn't always show up.
4. See that the Chromecast (named 'Google Cast') device does not show up.
5. Go to Wi-Fi settings page and assure that you are connected to same network as the Chromecast.
6. Still not showing Chromecast.
IMPORTANT NOTE: This behavior is intermittent, with about 70% of the time showing the unexpected behavior, and about 30% not showing. Please attempt to reproduce at least twice in troubleshooting. When you do, you must give it some time between successfully seeing the Chromecast, and troubleshooting again to see the issue. Usually 1 day reproduces the issue again. When working, Chromecast will stick to Spotify Connect on the Google Pixel for a while, and then when you come back to it in a few hours or the next day, it will present the issue again, which can take some 15-30 minutes to get working at times.
1. Assured that Wi-Fi on Google Pixel was on the same network as the Chromecast.
2. Factory Reset Chromecast Device. This fixed the issue for about 3-4 days maximum, and then it happened again.
3. Factory Reset Google Pixel. (Note that this was a step I was reluctant to take, but took for the sake of troubleshooting, and documenting it, as this issue has been persisting for months.)
4. Tested Chromecast from the same Device (Google Pixel) but with another Casting enabled App. Ex. Youtube, Netflix, etc. Was able to cast with no issues whatsoever. This leads me to believe this is an integration issue with the Google Pixel, and Spotify, because it is casting with ease from other apps on the Google Pixel, but not Spotify.
5. Had family member attempt to cast Spotify from Iphone, to which they had no issues whatsoever and were able to cast from Spotify with ease.
Note: This workaround only works if you have another second device that has Spotify on it and is connected to the same network.
1. If you have the luck of having another device around (Ex. Laptop, or other phone):
2. Open Spotify from that device (Ex. Laptop, or other phone)
3. Play music from Google Pixel where issue is ongoing.
4. Tap "Devices Available", and tap the 2nd device you are using (Ex. Laptop, or other phone)
5. Music will now be playing from second device (Ex. Laptop, or other phone)
6. Once music is playing on second device, and is no longer playing on your Google Pixel, click "Devices Available" on second device, and see that the Chromecast is available on the second device. Select it, and the music will be finally playing on your Chromecast.
7. See that your Google Pixel has been pushed to now see the Chromecast device, after you used the workaround.