Why does my L2TP/IPsec client disconnect when another L2TP/IPsec client connects to the same L2TP/IPsec server?
Only one L2TP/IPsec client at a time can connect to an L2TP/IPsec server via NAT with one public address. When a new client attempts to connect to the server via the same public address, the current client session is interrupted. This is a known technical limitation. If you would like to connect several devices to the same VPN server at the same time, consider using another service.