Custom code for a custom connector is not packaged within the solution file. After importing a solution containing a custom connector, the custom code assembly must be deployed separately to the target environment using the Power Platform CLI (paconn update). Importing a solution as managed locks its components, preventing further edits. Since using the CLI to upload the code is considered a modification, this action would fail on a managed connector. To resolve this, the solution must be deployed as unmanaged, which allows the connector component to be updated with the custom code in the target environment.

B. Deploy the solution as managed. Deploying as managed is best practice for production but would lock the connector component, preventing the necessary post-import step of uploading the custom code via the CLI.
C. Publish the connector in the development environment. Publishing a connector makes it available for use within the source environment but does not affect how its custom code is packaged or deployed to other environments.
D. Import a new solution with the custom connector. Simply re-importing the solution will not fix the issue, as the custom code is fundamentally not part of the solution package and requires a separate deployment step. ---

1. Microsoft Learn. (2023). Add custom code to a custom connector.

Section: "Deploy the connector"

Content: "When you import a solution that contains a custom connector with custom code, the code isn't deployed automatically. You need to deploy the code separately." This document establishes that a separate step is required outside of the solution import process.

2. Microsoft Learn. (2023). Managed and unmanaged solutions.

Section: "Managed solutions"

Content: "You can’t directly edit the components within a managed solution." This principle explains why the post-import CLI command to upload code would fail against a managed component, as it is an editing action.

3. Microsoft Learn. (2023). Solution concepts - Power Platform ALM.

Section: "Unmanaged solutions"

Content: "Unmanaged solutions are used in development environments while you make changes to your application. [...] You can export an unmanaged solution from a development environment and import it into another development environment as an unmanaged solution." This supports using unmanaged solutions to enable changes in the target environment.