Glad to know that you were able to figure this out and thanks for sharing the rootcause. By the way, Microsoft Q&A community has a policy that "The question author cannot accept their own answer, they can only accept answers by others.".
Hence request you to accept this as an answer so we can close this thread. I am summarizing the issue and root cause you have found for it.
Issue Summary:
user wanted to convert a CSV file to base64, encrypting it, and then sending it downstream. Once after the conversion the file size exceeds 4MB, rendering the use of lookup unfeasible for reading the file content.
Requirement:
Seeking alternative methods to obtain the base64 content from the files.
Solution:
- Initially, read the file and converted the content to base64 format.
- Then, utilized the GPG function via an External Call activity, constructing a payload and passing it along.
- Subsequently, read the response and wrote it back to a file.