Can't start over with new iPhone-backups after forgot password for encrypted copy on iTunes

I have forgot my password for the encrypted copy of my iPhone-backup on iTunes.

I am aware that it is impossible to retrieve the information from my backup on my computer.

I've made a full software restore and then set the iPhone up as a new device. After that I retrieved the backup copy that I had on iCloud.

I've started a new account on my computer and then connected my iPhone to iTunes.

However, when I connect the iPhone to iTunes the square for encryption is still crossed and when I try to uncross it it asks me for my old password.

Please help me solve this. I don't need to retrieve the old information on iTunes/the computer but I want to be able to start over with new backups of my iPhone on my computer.