Dear CoE,
I've been an irregular visitor here for some time - I created an account a year or so ago. The last few times I have tried to log in I was refused with the titular message: "Invalid login attempt".
It seems that my alphanumeric password (lacking symbol or punctuation characters) was no longer strong enough. Upon updating my password, I can now enter the website (and create this post.)
I would suggest that the generic error text be updated to suggest updating the password or offers a re-direct to a lower security, limited log in so a support post can be created.