Errro establishing database connection issues

My wordpress site is down and when i restart it again it’s up and running. Found the server logs following warning shows this
1.The log warning [MY-012985] [InnoDB] A long semaphore wait suggests a potential database lock or resource contention issue.
2.validate password plugin is deprecated and will be removed in a future release please use vaildate password component instead in wordpress
3. Error establishing database connection
WordPress version – 6.3
mysqli – Server version8.0.40-0ubuntu0.20.04.1
Server architecture – Linux 5.15.0-1075-aws x86_64
Web server – Apache/2.4.57 (Ubuntu)
PHP version – 7.4.33-SergeyD/6.1 (Supports 64bit values)

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Error message from server logs

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