Can`t Access Post Page After Migration

Deactivate all your plugins and themes reactivate the theme and the required plugins of the theme; check if you have no bugs if no errors reactivate the other plugins one by one and check if there are no errors. You can also follow this https://www.wpbeginner.com/wp-tutorials/how-to-find-and-access-wordpress-error-logs-step-by-step/ and share your logs

How to change Permalinks only for Blogposts

Review information here for changing permalinks: Setting Permalinks Look at Custom Structure and adding /blogpost/%postname%/ For custom post type permalinks you have to disable “with front” so they will not be appended with your custom structure. For automated redirects and monitoring take a look at this plugin: Redirection

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)