It’s working for me now.
Follow this guide: The easiest way to secure Home Assistant with HTTPS | dummylabs.com
And the last thing that did the trick was adding the below text to configuration.yaml
(in http section)
use_x_forwarded_for: true
trusted_proxies:
- 172.30.33.0/24
This do not seem to be working for me. Same error.
However I have not changed my SSL since I use the DuckDNS add-on, where you only get a token. This can not be used with the Nginx Proxy Manager (as far as I can see)
This is no longer a Sonos or a TTS issue. This is a DuckDNS/Nginx/HTTP configuration issue. My suggestion is to read some of the changes and specifically breaking changes of the past few major versions of HA (ie 2021.6, 2021.7, 2021.8) and if you run HA Supervised or HAOS, the supervisor and HAOS changes as well.
Hello,
Can you tell me exactly where to look on the information? I am completely Lost 
I have given up on TTS. Instead I have recorded my own MP3 announcements using the website https://ttsmp3.com/ - excellent range of languages and accents. If you save the files somewhere in the Sonos Music Library and make them Sonos favourites you can simply play them by filename.
This nags me to turn off the Xbox at 1am:
action:
- service: sonos.snapshot
data: {}
entity_id: media_player.study
- service: media_player.volume_set
entity_id: media_player.study
data:
volume_level: 0.4
- service: media_player.select_source
target:
entity_id: media_player.study
data:
source: xbox_off_1.mp3
- delay:
hours: 0
minutes: 0
seconds: 10
milliseconds: 0
- service: sonos.restore
data: {}
entity_id: media_player.study
Edit: The restore part of the automation above will not work if you are playing a playlist - the sonos.snapshot service does not capture playlist details. Instead you might try:
action:
- service: sonos.snapshot
data: {}
entity_id: media_player.study
- service: media_player.volume_set
data:
volume_level: 0.4
entity_id: media_player.study
- service: media_player.play_media
target:
entity_id: media_player.study
data:
media_content_id: http://homeassistant.local:8123/local/sounds/xbox_off_3.mp3
media_content_type: music
- delay:
hours: 0
minutes: 0
seconds: 10
milliseconds: 0
- service: sonos.restore
data: {}
entity_id: media_player.study
Your .mp3 announcements should be stored in the directory config/www/… in HA.
TTS up and running again. This solved it for me.
https://community.home-assistant.io/t/nginx-and-duckdns/262579
Then follow the dummylabs guide posted by Mackan.
If you get “400 bad request” when testing “basic HTTP access”.
https://community.home-assistant.io/t/home-assistant-400-bad-request-docker-proxy-solution/322163
Very strange. I don’t use Nginx and I don’t have any 400 bad request errors. Everything else works fine - is anyone else just using Duckdns and having this problem with Sonos TTS?
Same problem here. After installing DuckDNS sonos stop working for playing any mp3 behind my domain.duckdns.org.
I’m start thinking that this can be a problem with router nat loopback, where it recognize that the domain is inside your network and change the public ip for the private one to avoid going outside.
This for sure will cause https handshake domain validation to fail.
I will try to find that option in my router and check with wireshark also.
what i found out last night. is that if you are able to have a HTTP webaddress for local, and https for external access, it works.
today i will have more findings.
How do you make that work? I cannot figure out your settings for internal and external URL - will you share? Or am I on the wrong track? 
if you follow @Perka82 reply it will work. for me it didnt because when i try to create an new SSL it fails… I believe because of the Port forwarding on the router. But try it . thats what made me realize the issue for me.
But today i have my IT guy come in and Help me. After my findings, ill explain it all in my own way. I am not a Tec Guy. im just a normal guy trying to survive in this tec world
I have solved the problem by adding the lines to the http section:
http:
use_x_forwarded_for: true
trusted_proxies:
- 172.30.32.0/24
You can find the Hassio internal ip-range by looking into the Supervisor - Multicast logging.
example: mdns-repeater (6): dev hassio addr 172.30.32.1 mask 255.255.254.0 net 172.30.32.0
i have also solved my issue. and that was one of the options. if someone else needs help with this, let me know.
I added the below to the http section:
use_x_forwarded_for: true
trusted_proxies:
- 172.30.32.0/24
But still TTS is not working through Sonos. Could it be because of indentation?
I am using Duckdns with Let’s encrypt.
After following @Perka82 recommendation of installing Nginx as reverse proxy finally working for me also.
In my case I can confirm I have NAT loopback in my router but this solution seems to work with this with no problems.
@Soccs - How do you make that work? I cannot figure out your settings for internal and external URL - will you share a picture from you config?
Same problem. I am also using Duckdns with Lets Encrypt
@mdok @droopycool you need to install Nginx addon to get a reverse proxy in front of your HA. This will do that yo can work with http inside the LAN (Sonos works ok) and https from outside.
I have configured my duckdns as extenal and internal ip as internal in the http config yaml and it’s working good.
I am having a very similar issue here:
Blockquote* Failed to cast media https://xxxxxxxxxxxxxxxxxxxxx.ui.nabu.casa//api/tts_proxy/949c83284b4b508a3a54c0fb9082b64b0b49ae51_en-us_a9c18110b0_cloud.mp3 from external_url (https://xxxxxxxxxxxxxxxxxxxxy.ui.nabu.casa). Please make sure the URL is: Reachable from the cast device and either a publicly resolvable hostname or an IP address
Have obviously tried putting in the nuba casa address in the config yaml, Have not tried any port forwarding yet, but isn’t that the point of paying for the nabu casa cloud?
I added the below to the http section:
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use_x_forwarded_for: true
trusted_proxies:
- 172.30.32.0/24
For me the tts or playing an mp3 track is still not working.
I also use duckdns with Let's encrypt. My HA is installled on an Odroid.
I have an Intel NUC with Webserver (Port 80 and 443 forwared) where my various websites run.
If I wanted to install the Nginx reverse proxy I would have to install it on the Intel NUC rather than on the HA Odroid? Correct.