Unable to add Lightweight Social Icons to the top bar widget

Hi guys

I'd appreciate it if you could help me on something please.

I've been trying to add a couple of social media buttons to the Top Bar widget on my website.

I've tried both ways:

Customiser - widgets - top bar

also

Appearance - widgets - drag Lightweight Social icons across on to the Top Bar widgets. Add Facebook
Save but still nothing shows.

I'm working in offline mode ie Flywheel local, whether that has got any bearing on this?

Thanks in advance

Pat