first of all sorry for the late response. Real life and work was consuming too much from my time. Normally the port 7053 is correct, but you cannot connect to it with your browser, as it is not an HTTP based protocol, but you can open a terminal and enter
telnet aaa.bbb.ccc.ddd 7053
this should give you something like
Connected to aaa.bbb.ccc.ddd.
Escape character is ‘^]’.
and ask you for a prompt which you can terminate by QUIT
But if the autodetection of the bridge thing doesn’t work, it looks for me like an issue in the DL2 config. From the manual is seems, that there is an option to configure remote access, which you have to enable and configure the password accordingly.
Also note, that the VBUS/LAN network interface only supports one connection to the port 7053 at a time, so in case you also have configured access via Vbus.net (or use Resol ServiceCenter or the RPT tool at the same time) it will cause problems and I could imagine that for the DL devices it is similar.
Last but not least, I remember some issues with older firmware versions, so please check whether your DL2 is on the latest firmware from Resol and update if not.
I hope it helps, and look forward to your response.