Hi @denisgomes
This issue seems to be unrelated to the original as reported in this topic, and it is likely due to the server-side DNS cache.
What error message do you get when you try to reconnect those sites?
You can try setting your Action Logs to debug before attempting the Reconnect and Connection Test to get more details.
Flushing the DNS cache from the server where the Dashboard is hosted may help resolve the problem if DNS is indeed what’s causing it.