You need to forward the port that you configured BIMCloud to listen to so that it is accessible from outside your LAN.
Things to check:
- The computer/server that BIMCloud must allow connections to that port.
- The router/modem that provides internet access to that computer/server needs to forward data sent to it from outside the LAN to that port to the computer/server's configured port.
If you are not sure how to do those things you will probably need to refer to someone that has some networking knowledge.
For configuring the BIMCloud server see
here.