I've had that before on a previous device. Turned out to be some buried Google setting that didn't have full internet access. Trouble is I can't recall which setting fixed it. Has the general Google app got full access, including 'unrestricted data usage' at the bottom?It's this screen here.
Uninstalling, disabling, and updating methods make it work for some time, but a reboot brings it back to this.
I was able to enable it as long as I didn't reboot once I got it working. Once the reboot happens, it's back to restricted network access and being unable to download additional languages in love translate.
Happened during 2 clean flashes.