Alexa get disconnected from devices afte 30 minutes

Configuration Voice Assistant
1

Hi all,
I follwed step by step the guide to create an Alexa Skill to execute HA commands.
Using US AWS server for lambda function I was able to enable the skill on Alexa app ( I was getting an error using EU AWS but on this community I found that using US server resolved the issue).
Now the linking works fine, I can connect to Alexa and discover devices but after 30 minutes each time Alexa say Disconnected From server and devices are unavaliable. I need to disable and reenable the skill to get connected again, but after 30 minutes same issue.
Were I was wrong?

Thanks to all!

2

It turned out it was a firewall issue.
UTM Sophos firewall detects incoming AWS connections from Pitangui as a possible attack, I had to skip the Rule ID 950120 (owasp.org) into Common Threat Filtering. Perhaps it helps if anyone else reverse proxy HA behind UTM Sophos WAF .

Regards