Error when loading page

Warning: Trying to access array offset on value of type null in /wp-content/plugins/post-smtp/Postman/Postman-Mail/PostmanTransportRegistry.php on line 107 Fatal error: Uncaught Error: Call to a member function getFromEmailAddress() on null in /wp-content/plugins/post-smtp/Postman/PostmanWpMail.php:165 Stack trace: #0 /wp-content/plugins/post-smtp/Postman/PostmanWpMail.php(148): PostmanWpMail->createNewMessage() #1 /wp-content/plugins/post-smtp/Postman/PostmanWpMail.php(50): PostmanWpMail->processWpMailCall() #2 /wp-content/plugins/post-smtp/Postman/PostmanWpMailBinder.php(121): PostmanWpMail->send() #3 /wp-content/plugins/security-malware-firewall/security-malware-firewall.php(2439): wp_mail() #4 [internal function]: spbc_send_daily_report() #5 /wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Cron.php(121): call_user_func_array() #6 /wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Cron.php(54): CleantalkSP\Common\Cron->runTasks() #7 /wp-content/plugins/security-malware-firewall/security-malware-firewall.php(292): CleantalkSP\Common\Cron->execute() #8 /wp-settings.php(447): include_once(‘/var/www/vhosts…’) #9 /wp-config.php(106): require_once(‘/var/www/vhosts…’) #10 /httpdocs/wp-load.php(50): require_once(‘/var/www/vhosts…’) #11 /wp-blog-header.php(13): require_once(‘/var/www/vhosts…’) #12 /index.php(17): require(‘/var/www/vhosts…’) #13 {main} thrown in /wp-content/plugins/post-smtp/Postman/PostmanWpMail.php on line 165

What is causing this and can this be fixed please?

We use plugin version: 2.1.10
WP 6.1.1