Mobile Notification Problem

Summary
Mobile Notification Problem

Steps to reproduce
Mattermost Version: 5.39.0 Team Edition
Database Schema Version: 5.39.0
Database: mysql
OS: Ubuntu 20.04.3 LTS
Firewall Open port: 443, 80 on Mattermost Address
Using NGINX server whit Let’s Encrypt Certificate

Expected behavior
Hello,
I’ve configured a Matermost Team Edition on an Ubuntu Server as indicated above;
everything works fine except the IOS and Android App Notification.
I always get the “connection reset by peer” error, as you can see in the log below.

Do you have any advice to solve my problems?

Thanks for your time.

Regards

Observed behavior
Below is the log from notifications.log

{“level”:“debug”,“ts”:1633621257.4752905,“caller”:“app/notification.go:396”,“msg”:“Notification not sent”,“logSource”:“notifications”,“ackId”:"",“type”:“message”,“userId”:“8yzekdnp1ibczg3umdpoynwtnh”,“postId”:“1mdy78oqq3n38ms5wwr7yx4fte”,“status”:“Not Sent due to preferences”}
{“level”:“info”,“ts”:1633621257.4919362,“caller”:“app/notification_push.go:358”,“msg”:“Notification will be sent”,“logSource”:“notifications”,“ackId”:“a1q9wb1tbp8s7do84xsb3wujha”,“type”:“clear”,“userId”:“8yzekdnp1ibczg3umdpoynwtnh”,“postId”:"",“status”:“Prepared to send”}
{“level”:“error”,“ts”:1633621257.6260264,“caller”:“app/notification_push.go:106”,“msg”:“Notification error”,“logSource”:“notifications”,“ackId”:“a1q9wb1tbp8s7do84xsb3wujha”,“type”:“clear”,“userId”:“8yzekdnp1ibczg3umdpoynwtnh”,“postId”:"",“channelId”:“kmtkuii68pdtfeeap65b6oqagy”,“deviceId”:“da321b2efb57ewe68c03qad855420f66d69dba8c602c9d84e71a44bf97f0ccc9”,“status”:“Post “https://push-test.mattermost.com/api/v1/send_push”: read tcp 192.168.xxx.xxx:56572->23.20.88.200:443: read: connection reset by peer”}

Hello,

I understood the problem, there was a bad dns record on my domain, now notication work correctly.