create cluster match the license between 2 srx240 , I can't delete one license.

one of the prerequisites from [KB15504] to create a cluster is to match the license ,

I have one srx0 with

show system license usage                      
                                 Licenses     Licenses    Licenses    Expiry
  Feature name                       used    installed      needed 
  dynamic-vpn                           0            2           0    permanent
  ax411-wlan-ap                         0            2           0    permanent

and another srx1 with

show system license                
License usage: 
                                 Licenses     Licenses    Licenses    Expiry
  Feature name                       used    installed      needed 
  dynamic-vpn                           0            2           0    permanent

on srx0 I try to delete the license to have srx0 and srx1 the same license .

 request system license delete ax411-wlan-ap    
Delete license ax411-wlan-ap ? [yes,no] (no) yes 

error: ax411-wlan-ap: license key does not exist

any suggestion ?