That did it!
The new strongswan.conf is more like this:
charon {
start-scripts {
# creds = /usr/local/sbin/swanctl --load-creds # <-- this
line was the problem
conns = /usr/local/sbin/swanctl --load-conns # <-- this line
seems to imply loading creds mentioned in swanctl.conf
}
}