I get the approval mail. After Clicking it
You receive confirmation on your email address when suspicious or unusual activity is detected.(This means that your password is correct)
,I get the SMS code on my phone. I enter the code and try to login.
SMS code is a second layer verification.
I get the Error Decrypting error msg. There is something wrong on the Block chain.info side.
this means you activated Advanced security: "Login IP Restriction"
Only allow login from IP address in the whitelist. If you do not have a static IP address, this may lock you out of your wallet. If you have verified your email address, you will be notified of any suspicious login attempts.
Since you are lost access to your backup phrase, uncheck any program that changes your IP or tor projects with full deletion of all browser files and you will be able to access your wallet.