Magento Site Down Due Error 521

[nomankhan978db]

I am running magento on debian linux VM in GCP. After upgrading the memory and disk space. My site is down. Showing error 521. I have checked the issue. MariaDB is not starting.

Found these errors: Found recent error or warning messages in the Apache error log.

[Mon Jan 10 09:08:13.364341 2022] [core:error] [pid 4368:tid 140527437379328] 
[client **ip_address**:34926] AH00126: Invalid URI in request 'bin/sh' 'POST 
/cgi-bin/.%2e/.%2e/.%2e/.%2e/bin/sh HTTP/1.1'
 [Mon Jan 10 21:03:41.071801 2022] [authz_core:error] [pid 4369:tid 
140527898978048] [client **ip_address**:33340] AH01630: client denied by server 
configuration: 
Press [Enter] to continue:
/magento/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
 [Mon Jan 10 21:26:06.307524 2022] [authz_core:error] [pid 5913:tid 
140526657414912] [client **ip_address**:40196] AH01630: client denied by server 
configuration: 
/magento/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php

[LitCommerce Expert]

You can use third-party tools like cURL or Telnet to test origin server response.
For the example commands shown below, you need to replace IP address 1.2.3.4 with the IP address of your origin server. Also, you can run these tests against port 443.
Windows users can test a connection using Telnet (via the Command Prompt).
Run a command similar to this:

telnet 1.2.3.4 80