Manual update no longer working

I have an Olimometer running on a site, and it has been working fine up until now. The total raised has been being updated manually and displaying. But now when a new total is entered, it no longer updates the Olimometer with the figure.

I tried creating a new olimometer to replace it with, but that didn’t work because the format we want – thin blue progress – didn’t show, instead it kept with the default thermometer.

I also tried disabling all other plugins to see if there might be a conflict, but it made no difference.

Is this a known bug, perhaps caused by recent WP updates. Is there a solution or should I find another plugin?

Thanks for your help.

https://wordpress.org/plugins/olimometer/