In your case you are entering an incorrect account password.
Given that you recently updated your password, I suggest attempting to revert to the last known password by following these instructions.
Please don't send me more of your recommendations. I am tired of your suggestions and links to read different articles. I know what I am doing and I have been a Last Pass customer since 2014! I have never experienced any issue with Last Pass until the latest update in May 2023.
Last Pass must contact every user (individually, one by one) and solve the login problem. We are not IT or security-trained people, we are just normal users. Something went wrong in the Last Pass update and Last Pass must resolve this problem, not us!
@AshC_LP Well, for some reason, that worked.
I don't know why attempting to login via the addon was failing with that message, but logging in via the website itself worked, and made the addon login too.
I can only assume there's been some change to the back-end that caused my older version of the addon (4.66) in my older browser to fail to authenticate properly.
So, consider my case closed.
Today I received an email from Last Pass informing me that I never changed my Master Password.
Therefore I logged in with my old password (not the new one which I created in May 2023) and EVERYTHING WORKED!!!! I received the email from Last Pass to verify that it was me and I accessed my account!!
My case is now closed, but it looks like I am losing my memory because I was 100% sure (and still am 100 % sure) that I did change my Master Password in May 2023.
You are not crazy!
This is exactly how I got back into my vault.
I used a password that I created in 2019 (which was subsequently changed by me three times)!
They told me I never changed my password and oh by the way, they also told me they don't have access to our passwords.
I've explained the entire nightmare in this thread if you want to learn more.