Below is what worked for me and some lucky ones. Steps were shared last year by one of the members here:
1. Logged in with GC Key account.
2. Permanent Residence > Family Class (Spouses)
2-a. Application Number and Family Name - Copy/pasted application number from email (including the F) and entered PA's last name.
3. City of Birth - I entered 1 space (hit spacebar once)
4. Country of Birth - Selected PA's country of birth
5. Passport Info - Did not enter any passport info
6. Other Application Info - Filled out the other application info as per our application and put '2' as the number of members in the application. I am sponsoring my husband, no dependents.
Again, for 2-a, I selected Family Name, Given Name, Birthday (This is Principal Applicant's (PA) info).
On no. 6, I entered '4' because I have 2 dependents.
To some, it worked for them by entering all of the passport details.
Good luck!