Same problem here, I didn't forget the password but it doesn't work at all and I don't remember changing it. I have even the secondary password memos and all but it doesn't work.. first it worked on the PC only and the phone was giving an error, and now on none of them: both got the same error. Contacting the support will only give you one answer: the only way you can do anything is to restore an older wallet backup if you have one. But keep in mind that it doesn't also restore the imported addresses. This is the problem I am facing: it restores everything but the imported addresses... Which are exactly the ones I got money into. RIP my money

maybe you can make a full backup restore from the point where you had no secondary password.
If you have an old blockchain wallet account that keeps asking you for a second password (although you never had any) to let you log in and denies you access every time you put any; I can help you access that account if you still have the correct password and know the email address you registered with; You can come to me for help only if you are 200% helpless and clueless and are 200% sure that you can't get help from blockchain.com support or anyone that you know. I can be your last resort and I will help you have access to the account but for that I will charge you 50% of whats inside the account. I can prove myself to you if you can provide me any dummy account prior to accessing the one in question.
P.S.; Come to me only when you have tried elsewhere and didn't get any result.