Forum account links

[zombeast]

Sorry, the forum account supplied is currently unavaliable for a swap. The email address under the vBulletin account zombeast must match the contact email
address under the client account with forum account linked. Please contact support if you need help resolving this error. (EC_MISMATCH)

zombeast has the email "1" while the client account I want it linked with has the email "1" also.
The other client account has email "2" and the other forum account has email "2" also. What's wrong?

Client account "2" is linked with forum account "1"
and Forum account "2" is linked with client account "1"