I am using WordPress for my websites and I hosted it in AWS lightsail with cPanel WHM. However, The SMTP of the website added in cPanel is not working. I am using a plugin called Easy SMTP.
I tried to test the email but it's says 'Could not connect to SMTP host. Failed to connect to serverSMTP server error: Failed to connect to server SMTP code: 111 Additional SMTP info: Connection refused', even though my credentials are correct and SES are verified. By the way I manage the DNS records in Cloudflare.
Have you tried checking your cPanel Firewall?
Please try navigate to Plugins > ConfigServer Security & Firewall > Firewall Configuration
And Look for SMTP_Block, also try to check if it was enabled and if it was enabled make sure to disabled.