Good news! I have updated the module to swap the data provider to a new one (that seems to be more reliable and provides the most recent available data and, some additional ones too!)
The changes are still on a development branch, so if you are interested in trying them out you can do the following (assuming you are in your Magic Mirror module folder for MMM-covid19):
git fetch -p
git checkout feat/new-api-corona-lmao-ninja
git pull -r
npm install
the configuration does not require any update, but a few settings are now obsolete and not used, this is how the new configuration settings could be looking like:
countryCodes: ["DE", "IT", "US", "NZ", "UK", "FR", "IN", "ES", "BG", "GR"],
useScheduler: true,
schedulerConfig: '0 0 */1 * * */1', // update every hour, every day
updateInterval: 0.5 * 60 * 1000, // update every 30 seconds, only used if useScheduler: false
and here is a screenshot:

and here is the GitHub repo:
https://github.com/0m4r/MMM-covid19/tree/feat/new-api-corona-lmao-ninja