The customer will need to check their network/firewall settings to ensure that they are allowing traffic to the required Business Partner addresses on port 443. The customer may need to contact the Business Partner for these addresses.
If the SAL Gateway is pointing directly to Avaya, then the customer will need to check their network/firewall settings to ensure that they are allowing traffic to the following Avaya addresses on port 443:
198.152.220.247 secure.alarming.avaya.com
135.11.107.20 remote.sal.avaya.com