Experiment not registering keyboard online builder MAC

URL of experiment:

https://run.pavlovia.org/Moore/tarea_nback/?__pilotToken=c9f0f895fb98ab9159f51fd0297e236d&__oauthToken=ca3d0a0f8922fdd37c1d67ba6840b1098c367fdf35da4c05df177fbae5612e8b

Description of the problem:
The experiment accepts yes/no responses using ‘b’ and ‘m’ as acceptable inputs.
The experiment runs fine and correctly saves keyboard presses on non-mac computers.

However, on my mac laptop (late 2011; macOS high Sierra version 10.13.6) it doesn’t save ‘b’ and ‘m’ responses, although it does save ‘left’ and ‘right’ responses. Also, when running the experiment in the builder offline, it correctly saves ‘b’ and ‘m’ responses from my mac. It may be worth noting that I’m trying to run the experiment in Spain? Although I’m just guessing, really

Thanks for any help.

Regards,