Hello Jae,
I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer.
Issue: Unable to Connect Azure SQL database from Azure Data Factory
Error: Cannot connect to SQL Database
Solution:
The issue turned out to be a password problem. The error was resolved after inputting the correct password.
If I missed anything please let me know and I'd be happy to add it to my answer, or feel free to comment below with any additional information.
Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.