BUG #18358: I am not able to change the existing SQL connection to Postgres connection in existing application

The following bug has been logged on the website:

Bug reference: 18358
Logged by: Noordeen zikutheen
Email address: noordeen(dot)sf3844(at)gmail(dot)com
PostgreSQL version: 16.2
Operating system: Windows
Description:

I changed the connection strings in the web.config file

and added connection strings, Entity Framework code and System.Data code.

But we are getting exception like this

Keyword not supported: 'port'

And when we tried to scaffold the PostgreSQL database in the dotnet 5, 6, 7
console app, we are getting error like this

Exception data:
Severity: FATAL
SqlState: 28000
MessageText: no pg_hba.conf entry for host "10.136.66.234", user "doadmin",
database "defaultdb", no encryption
File: auth.c
Line: 535
Routine: ClientAuthentication 28000: no pg_hba.conf entry for host
"10.136.66.234", user "doadmin", database "defaultdb", no encryption

enter image description here

We have a project and class library in .NET 4.5 and we are using Microsoft
SQL Server as database and we want to migrate the database into PostgresSQL.
I tried but I'm unable to migrate with the existing DbContext file. I didn't
get a solution for this yet

I am currently trying with the new console app in dotnet 8 and from
scaffolding method created models and DbContext file, again I am working
from the beginning. And from other dotnet version I was unable to scaffold
so gone with dotnet 8.

Can I have any solution to migrate from Microsoft SQL Server to Postgres
SQL?