I can confirm this issue. I've installed two virtual machines, one with Ubuntu 18.04 and another with 19.04. In the two machines I only have installed updates and ssmtp package. With the same configuration in both, the ubuntu 18.04 works correctly but the 19.04 not. The error is the same as Walter says.
I can confirm this issue. I've installed two virtual machines, one with Ubuntu 18.04 and another with 19.04. In the two machines I only have installed updates and ssmtp package. With the same configuration in both, the ubuntu 18.04 works correctly but the 19.04 not. The error is the same as Walter says.