"There was an error during playback"
Comes up whilst watching Freeview On Demand programmes. The frequency of this message is increasing. Used to be once or twice a week but now several times a night. Occurs in any programme we happen to be watching so right now it's Top Gear & The Musketeers for eg. Once the error appears, the programme cannot be watched nor when accessed later will it remember where we left off. 
Switching off at the wall and waiting does little to improve the problem. Resetting modem makes no discernible difference. 

D/L speed: 19.61Mbps
LGTV
UK6400PVC
webOS version 05.10.45
LG Content Store says Freeview version 11.0.8 (Updated 11/12/2018)
But the app itself says version 1.14.7, (Last updated 29 April 2020)

Any help most appreciated... Thanks.