Wordpress Migration Issue 503 error - database

Question

Recently I have revamped a website which is created on a development server. Then after that i started migrating it onto the main server. Initially I got a unicode error while uploading the database on the live server. I googled it and found a solution on stack overflow itself (#1273 – Unknown collation: ‘utf8mb4_unicode_520_ci’). I used the method suggest by sabba and it worked. Later when I Changed the config file and loaded that link. Its giving me a 503 error.. It error is as follows:
Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
Additionally, a 503 Service Unavailable error was encountered while trying to use an Error Document to handle the request

Answer 1

Go through the steps and check it,
Enable WP_DEBUG
But since the 503 error often locks you out of your WordPress admin, we shall use WP_DEBUG and WP_DEBUG_LOG, WP_DEBUG_DISPLAY and #ini_set constants available to WordPress.
To enable debug mode in WordPress and write errors to a log file, follow these steps:
1. Open the wp-config.php file
2. Scroll down to where WP_DEBUG is defined. It looks like this define ('WP_DEBUG', false);. If it is missing, we will add it just above the line that says /*That's all, stop editing! Happy blogging.*/
3. Insert the DEBUG magic codes. Just change the above define ('WP_DEBUG', false); code to:
define ('WP_DEBUG', true);
define ('WP_DEBUG_LOG', true);
define ('WP_DEBUG_DISPLAY', false);
#ini_set ('display_errors', 0);
4. Save changes
Now, reload your site to provoke the error. Next, locate a file known as debug.log inside your wp-content folder in your WordPress directory.
This file contains all the errors on your website. If your 503 service unavailable error is caused by a custom code snippet, it will show up somewhere with details of the error.
Eliminate/replace the problematic code and reload your site. If the 503 error persists, the problem could lie in your web server.