Cannot connect ASP .NET container to mssql container - asp.net

Question

I have an ASP .NET app in a container that I am trying to connect to a mssql container (running in the same network) but no matter what I change in the connection string, my app still crashes Unhandled exception. Microsoft.Data.SqlClient.SqlException (0x80131904): Login failed for user 'sa'.
My docker file looks like this:
services:
dotnet_be:
build: "./"
ports:
- "5000:80"
depends_on:
- db
db:
image: "mcr.microsoft.com/mssql/server"
environment:
SA_PASSWORD: "Your_password123"
ACCEPT_EULA: "Y"
And my connection string looks like this:
"ConnectionString": "Server=db;Database=DeskBooking;User id=sa;Password=Your_password123;Trusted_Connection=False; MultipleActiveResultSets=true; Integrated Security=False;"
I am using db as server as both services are within the same network and they are accessible via the container name.

Answer 1

Try this
services:
db:
image: mcr.microsoft.com/mssql/server
container_name: db
environment:
- SA_PASSWORD=Your_password123
- ACCEPT_EULA=Y
restart: always
ports:
- "1433:1433"
dotnet_be:
build: "./"
ports:
- "5000:80"
depends_on:
- db
Note: No double quotes around password, eula and image.
Connection string is thesame

Answer 2

Probably you do not respect password security requirements.
Try this changes:
services:
dotnet_be:
build: "./"
ports:
- "5000:80"
depends_on:
- db
networks:
- my-network
db:
image: "mcr.microsoft.com/mssql/server:2019-latest"
container_name: db
ports:
- "1433:1433"
environment:
MSSQL_SA_PASSWORD:1hisIsStrongPwd!!
ACCEPT_EULA:Y
networks:
- my-network
"ConnectionString": "Server=db;Database=DeskBooking;User id=sa;Password=1hisIsStrongPwd!!;Trusted_Connection=False; MultipleActiveResultSets=true; Integrated Security=False;"
Check for errors with docker logs containerId, where containerId is the container from docker ps.