Sometimes people have more than one account in COSY. This is because they at some point in time registered with different mailaddresses.
When this happens, it might be that history and certificates are only visible in the one account and not in the other.
TO SOLVE THIS, you need to merge both accounts. You can do this by adding the email from the second account to the one you will keep as main account.
You can do this yourself by logging into CoSY
1/ select account from the left menu
2/ add secondary mail addresses
once done you will see the following message
3/ Go to the mailbox of the email address you have added and click the link to confirm.
IF this email was already linked to an account in COSY, both accounts will now be merged!