New install of Heyu gives error - 'Can't open tty line. Why???

[three-jeeps]

My older version (2.10) of heyu was running fine for a number of years. One day it just stopped. Restarted the machine and heyu which stated: Can't open tty line....check permissions. Absolutely nothing was done with this PC, running ubuntu server 16.04 except periodic updates. Tried to fix by changing permissions on ttyx and USB devices to no success....
Few months later, it started workning on its own. Continued for ~2 weeks, the back to the same error.

Months went by and I decided to install heyu on a new machine, Ubuntu v 18 server. Installed heyu, started it and same error: Can't open tty line, Check the permissions......wtf?!?!?!
Is this an OS error or a Heyu error?

I checked my FDTI usb - serial cable, it works fine. The same one I've been using on the original machine.
I am at a loss on how to fix this problem....any suggestions appreciated.

J.

[three-jeeps]

I should add that I tried to figure this out but nothing seemed to work...
As root: chmod 777 /dev/ttyS0

I also checked to see if I was belonged to the dial out group, which is was, but did this anyway: sudo usermod -a -G dialout $USER
rebooted the machine with no joy
in my config file I am using:
TTY /dev/ttyUSB0
#TTY /dev/ttyS0
#TTY /dev/tty0

This is really driving me nuts....worked for many years then all of a sudden, not working....grrrrr

[three-jeeps]

I solved my the issue on my machine and through I'd pass along the cause and the solution, and my approach to solving it. Since I use the FDTI cable with the embedded usb to RS-232 cable I thought the cable might be fried so I loaded a version of Active Home onto a win 10 PC and was able to control all my x10 devices. This ruled out the cable being defective.
When reinstalling the cable on my Ubuntu PC, I inserted it into a different USB port. Ran Heyu and it worked! Switch the cable back to the original USB port and got the cant open tty line error. Checked the usb status with lsusb, checked mounted USB devices, etc and all looked fine. Must be an electrical connection problem as Ubuntu seems to show the port is OK.

Then I moved on to finding out why ssmtp quit working and found out that relaying through gmail now requires the device to be registered in gmail and google will issue a password that the device will need to use. That cured the ssmtp problem.
So, case closed.