It appears that the le_data routines do not work over the ECM interface with the host. Marked solved to close the question. Looks similar to this problem:
Hello
David Frey posted this in the mangoh forum November 2017:
I talked to a couple people on the Legato team and they mentioned that the reason you cannot connect to AirVantage using the ethernet connection on the mangOH Green is that the ethernet connection isn’t supported by the data connection service. The data connection service is responsible for establishing a data connection to the internet on demand. This is a known issue and there is some interest internally in improving the data c…