Runner 4G (KN-2211)
OS 4.0.4
It is also impossible to delete SMS in the web interface. However, sometimes after a reboot you can delete several SMS. Then the option to delete SMS does not work again until reboot.
(config)> sms UsbLte0 delete nv-3
Mobile::Sms::Manager error[268239258]: "UsbLte0": system failed [0xcffd019a].