500 Internal Server Error - Azure Function through Data Factory using Postgres DB - postgresql

Question

I am trying to edit someone else's azure function app. When I run theirs, it works fine and connects to their DB successfully. When I try and change the connection string to my DB it gives me the error
HTTP response code: 500 Internal Server Error
without any other information.
Even if I just change the one line of code which defines the DB connection, it doesn't work. I have tried it on my local machine and it works, it just doesn't work in Azure functions.
Their original code (which works):
postgresql = os.environ.get('POSTGRES_SQL')
cnxn = psycopg2.connect(postgresql)
vs. mine (which doesn't work):
postgresql = 'postgresql://sqladmin:{my-password}#{db-connection-string}?sslmode=require'
cnxn = psycopg2.connect(postgresql)
I am also not sure where their DB connection comes from, using ".get('POSTGRES_SQL')", as they don't pass that parameter in anywhere. Below is how they call the function in Azure Data Factory, note that no parameters are passed in (nor anywhere in the function):
Even I try just a bare bones block of code as seen below, it gives me the same error.
def main(req: func.HttpRequest) -> func.HttpResponse:
postgresql = 'postgresql://sqladmin:{my-password}#{db-connection-string}?sslmode=require'
cnxn = psycopg2.connect(postgresql)
cursor = cnxn.cursor()
cursor.execute("CREATE TABLE staging.test (some-column varchar(100) null)")
cnxn.commit
cursor.close()
return func.HttpResponse(f"This HTTP triggered function executed successfully.")
Please let me know what I'm missing, or if you need any other info. I have already tried all other responses to similar StackOverflow questions.