Hey!
This "tutorial" is for the people who lost their Secondary Password for Blockchain. This probably only works for the older users (those who have been using Blockchain since the previous UI), but newer adopters should try it too. Hopefully, you'll get your funds back.
So I had a wallet (on my previous e-mail) on which I had some funds. One day, suddenly, my secondary password stopped being recognized. I have been using Blockchain since 2013 though, and in 2015 or 2016 they updated the UI and added the "Transfer Funds" feature. Looking through my lost account I noticed my addresses were "Imported" so I thought there's no way I could get my private keys. Months later, I entered my e-mail and made a quick search with the keyword "Blockchain", and scrolled down to my very first received e-mails. The second one I got had a "wallet.aes.json" file attached to it, which I downloaded and imported at
https://blockchain.info/wallet/import-wallet, which imported my lost account without a password.. and that's how I got my funds back.
What happened is probably because of the new UI. They changed it and made the upgrade mandatory. I never opted for it because I always saw the old one easier to use, and it worked for a few months after which I was "forced" to do it. As soon as the new "Transfer Funds" feature has been added, my usual BTC address has been moved to the "Imported Addresses" list. In the beginning I thought there's no way to recover my funds because the imported addresses are NOT included in the JSON file you receive in your e-mail, but for me it worked.
I hope I helped you get your funds back. This is how I got mine, so long after trying thousands of password combinations and even asking some wallet recovery services for help.
Have a great day!