I believe task timeout can also occur when you do not have the proper configuration to connect to your db cluster. Have you re-re-re-reconfirmed the ip? Are you going through a ec tunnel to get to your db? Is this running in AWS? I know the default config on aws is that you cant connect directly to the DB, you have to create an EC2 to use as a tunnel, and ensure the ec2 has a security group allowing external ips, and must also be in AWS’s internal subnet - the same as your DB is. I’m assuming both are in AWS.
Sorry I’m making a lot of assumptions here but maybe you can at least check that as a non issue if you’re already familiar and have checked these settings, or share with us roughly the configuration you have going on here.