RT database inaccessible

Hi all. We recently installed an RT 4.4.4 on a Debian 11. After a few configurations, I dropped its original db and then imported the db of RT 4.4.2 (which was our current RT on a different server) via MySQL Workbench. We were doing an upgrade from 4.4.2 to 4.4.4. After importing successfully, upon accessing RT on the browser, it shows an error: Database inaccessible; contact the RT administrator (support). But the db credentials on RT_SiteConfig are correct, and the newly imported db was accessible via MYSQL workbench and MYSQL command line. Kindly help. Thanks in advance!

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What do you see in the web server error log?