Push notifications not working on mobile

Hello.

I installed Mattermost via Docker using the included NGINX. Everything works fine except for the push notifications on mobile phone.

When I log in on my phone, I see this warning message:
2024-01-26_10-31-23

Push notification settings:

Log messages:

{"timestamp":"2024-01-26 05:32:41.450 Z","level":"info","msg":"Notification will be sent","caller":"app/notification_push.go:444","logSource":"notifications","ackId":"r3tqjj9cj7g7dewas4t68qot5o","type":"clear","userId":"qdnnmzxdhp893d1f5qnemu8gqw","postId":"","status":"Prepared to send"}
{"timestamp":"2024-01-26 05:32:44.572 Z","level":"error","msg":"Notification error","caller":"app/notification_push.go:131","logSource":"notifications","ackId":"r3tqjj9cj7g7dewas4t68qot5o","type":"clear","userId":"qdnnmzxdhp893d1f5qnemu8gqw","postId":"","channelId":"iwqubkh5pfgmzq1gqzoxi87t3o","deviceId":"651fc0d8dc96f93723beb662f7d379a07ee18cb717f5cb0ec6f38c78271578c1","status":"Post \"https://push-test.mattermost.com/api/v1/send_push\": net/http: TLS handshake timeout"}

Please tell me what I have to do to make it work properly. Thank you!

See if Mobile apps FAQ — Mattermost documentation helps.

Thank you. Documentation didn’t help.
I ran this script in container shell and didn’t get any response

curl https://push-test.mattermost.com

ran this command:

sudo docker exec -ti c9ffed7a844e curl -v https://push-test.mattermost.com

answer:

*   Trying 3.94.16.185:443...
* Connected to push-test.mattermost.com (3.94.16.185) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
*  CAfile: /etc/ssl/certs/ca-certificates.crt
*  CApath: /etc/ssl/certs
* TLSv1.0 (OUT), TLS header, Certificate Status (22):
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* OpenSSL SSL_connect: Connection reset by peer in connection to push-test.mattermost.com:443 
* Closing connection 0
* TLSv1.0 (OUT), TLS header, Unknown (21):
* TLSv1.3 (OUT), TLS alert, decode error (562):
curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to push-test.mattermost.com:443 

Сan someone help?

What does openssl s_client -showcerts -connect push-test.mattermost.com:443 </dev/null return?

ran this command in mattermost docker container:

sudo docker exec -it 36b3066f6195 openssl s_client -showcerts -connect push-test.mattermost.com:443

output:

CONNECTED(00000003)

and nothing else…