Nothing about this, however, in your config.toml you MUST specify audio_sps=12000 because if you don't it will NOT decode.
Other problem is ofhen that the system-clock of your PC isn't running correctly.
Simple and fast way to correct this is to install chrony.
apt install chrony
Edit chrony: nano /etc/chrony/chrony.conf
Make sure it look like this:
pool ntp.ubuntu.com
pool pool.ntp.org
rtcsync
makestep 1 3
# leapsectz right/UTC ----- YES this one must be disabled!
All the rest isn't that important, can be best left default.
Now restart: systemctl restart chrony
Then run: chronyc sources (wait until you see the servers show (37)7 - beware can take 10 minutes!)
When they do run: chronyc tracking
Then it should show the correct time and date, within less then 1msec, normally.
Chrony will keep your system on time every x minutes....automatically, never look back ;D
FT-8 is a precise-time-protocol, so wrong time means no decoding.
Typical test 7074KHz USB then click FT-8 and after 30 seconds or so it should show stations.