Hello Community,
We are using Moodle 3.11, Boost theme, own server.
For the first time yesterday, we cannot log into Moodle using the same Admin credentials that we have been using for weeks; this is the message received:

This is even more odd because we successfully logged into Moodle earlier in the day yesterday with the same Admin credentials.
No username or password changes were made to the Admin credentials.
We may try the 'forgotten...' re-set option:

But it would be good to know why this happened? (so we can explain why this happened and more importantly, prevent it from occurring again).
Any other suggested fix? Anyone else experience same and fixed?
Have read https://docs.moodle.org/311/en/Administration_FAQ#I_have_forgotten_the_admin_password
Thanks,