Error send key to keyserver

Please Help

1. i tried to send key to keyserver, by following user's guide.

 pgp --keyserver-send user1@example.com --keyserver ldap://keyserver.example.com

  Show error 3090:operation failed, Server is unwilling to perform

2. i tried to check connection with search key another user. it's work

 pgp --keyserver-search user2@example.com --keyserver ldap://keyserver.example.com

ldap://keyserver.example.com:keyserver search (2504:successful search)
 Alg  Type Size/Type Flags   Key ID     User ID
----- ---- --------- ------- ---------- -------
 RSA4 pub  2048/2048 [-----] 0xB40B23F7 user2
1 key found