cURL error 6: Could not resolve host


Feb 28, 2022
I got this error from Mumara dashboard:
cURL error 6: Could not resolve host:; Unknown error (see

Before error, I have change the innodb-buffer-pool-size from default value to 6G.
Why is 6G? The story is below:

My VPS has 30GB of RAM
I have some problems when I run a campaign with a big list.
I changed the innodb-buffer-pool-size from default to 15G following this post:
But then I got a lot of errors, including the error of this question and I cannot access to PowerMTA Managment Console.
So that, I returned the setting back to default --> The errors disappear.
Then I following this article:
I run the query in the red square bellow to calculate the optimum innodb-buffer-pool-size
The result is 6G
--> After changing, the error appears again.