Step 1 : Enable remote access for MySQL server using the documentation at MySQL Remote Access

Step 2 : Refer to steps 4 and 5 of the above mentioned documentation, and add the following value in the 'Additional Access Hosts' field

172.16.26.%

Step 3 : In your NodeJS codebase or in the concerned .env file, use the value 172.16.26.1 as the DB Host

Using the above steps, your NodeJS App should be able to access MySQL server on the N99panel VPS.