Failed to launch locally - MongoDB not connecting on Accounts

[pavlosidelov]

From the Article for Local launch a lot of things is unclear.
For example about DB

Get your mongo connection string. Almost all your microservices need it; keep it safe!
Ok, I save it in .env:
MONGO_URL=mongodb://$USERNAME:$PASSWORD@e07eca23-91af-413b-8bf6-3e3f9825717c-0.497129fd685f442ca4df759dd55ec01b.databases
BASE_PATH=e07eca23-91af-413b-8bf6-3e3f9825717c-0.497129fd685f442ca4df759dd55ec01b.databases.appdomain.cloud

When I do "npm start" on /accounts/ folder, I got a lot of missing components and I setup all of them, but the error still threw.

Running on e07eca23-91af-413b-8bf6-3e3f9825717c-0.497129fd685f442ca4df759dd55ec01b.databases.appdomain.cloud:3400, connecting to mongodb://$USERNAME:$PASSWORD@e07eca23-91af-413b-8bf6-3e3f9825717c-0.497129fd685f442ca4df759dd55ec01b.databases.appdomain.cloud:31892,e07eca23-91af-413b-8bf6-3e3f9825717c-1.497129fd685f442ca4df759dd55ec01b.databases.appdomain.cloud:31892/ibmclouddb?authSource=admin&replicaSet=replset
(node:20293) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'onOpen' of undefined
at /home/pavlo/prj/innovate-digital-bank/accounts/server.js:12:16
at promise.then.err (/home/pavlo/prj/innovate-digital-bank/accounts/node_modules/mongoose/lib/connection.js:394:53)
at
at runMicrotasksCallback (internal/process/next_tick.js:121:5)
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickCallback (internal/process/next_tick.js:180:9)
at Function.Module.runMain (module.js:695:11)
at startup (bootstrap_node.js:188:16)
at bootstrap_node.js:609:3

What I'm doing wrong and how to resolve it?
Thank you!