Azure DevOps Pipeline Azure SQL Deploy won't work with SQL script (Failed to login)

Question

I've been trying to deploy a database via a pipeline from Azure DevOps to an Azure resource group.

I have an ARM template for my database server in my Repo along with my DACPAC file. In my release pipeline I first deploy the database server with an admin user defined in the ARM template to my resource group. Then I use the "Azure SQL DacpacTask" to deploy the database schema. Here I give the admin credentials and it works flawlessly.

The issue is that the customer doesn't want it deployed as a DACPAC but rather an SQL script. They've given me a "CREATE TO..."-script from their database, created inside MS SQL Studio, which is also in my Repo.

The "Azure SQL DacpacTask" inside my release pipeline has an option for using an SQL file instead of DACPAC, but it doesn't work for me.

But no matter how I do it, my pipeline fails when running the "Azure SQL DacpacTask" and all I get, even in debug-mode is "Login failed for user '***'".

I can connect to the SQL Server through MSSQL Studio on my local machine using the admin credentials defined in my ARM template.

I've tried by adding the agent's IP before running the SQL script, but with no success.

Can anyone point me in the right direction or maybe tell me what I'm doing wrong? Why is it that it keeps failing to log in?

They want it deployed with little to no human interaction. Is it doable only through the ADO pipeline?

EDIT Additional info:

• I have tried with hardcoded password and user with no luck.
• If I manually create a database and then try to deploy one via script and pipeline, it fails because a database already exists, and not because of a failed login.
• I've setup Audit in Azure which generates 2 files with little to no info. I'm not sure what I'm looking at.