ODK Aggregate 2.0 - change URL not able to download exported csv

1. What is the problem? Be very detailed.
Existing ODK aggregate server 2.0 hosted in digital ocean just suddenly does not allow the existing url to be accessible in both the ODK Collect and ODK Aggregate server. Previously, it was ok but just suddenly, was not able to connect.

2. What app or server are you using and on what device and operating system? Include version numbers.
using digital ocean droplets to host the odk aggregate server using ubunto

3. What you have you tried to fix the problem?
I bought a new domain name and edited the settings in the digital ocean's server settings. I am able now to access the odk aggregate server. I have exported the data uploaded in the aggregate server as a .csv file. However, when I click the link for the csv file in the exported submissions, it still carries the old/previous url - this results in the error that the csv file is not found (precisely because the link still carries the old url).

4. What steps can we take to reproduce the problem?

5. Anything else we should know or have? If you have a test form or screenshots or logs, attach below.

My question is, how do I change or edit any settings in ODK aggregate server so that when I export a csv file, it will carry the new URL in the exported submissions page.

By the way, the ODK Collect cannot pull the forms from the server even if i have already changed the server settings on the application. It is able to display the existing forms but not able to download any forms. It still uses the old url. The error message says: Unable to resolve host (old url): No address associated with hostname Copying media files failed.

Also, the ODK Collect cannot send data to the aggregate server. The message says: Unexpected redirection attempt to an different host: https://(old url).