You have to follow this guide for both ArquatiPBX (52.57.247.41) and ArquatiPBX_bkp (35.156.113.252)

First, you need to turn on the backup server.
You can do this on AWS by clicking on this link.
Once the page is open, search for the ArquatiPBX_bkp server, select it, click on the Instance State button


and select start instance.

Open the sysmgmt, click on Phone System > Trunks and click Asterisk2

Follow this step for both ArquatiPBX and ArquatiPBX_bkp

1. Click on FreePBX Administration and login
   
2. Connectivity > Trunks