The administration icon indicates that it is administration server for the Directory.
Kindly check if issue is being reported on one admin client or on all admin clients. Also, ensure that the change of administration server is replicated across all servers.
Kindly try to Refresh the Server List. Open Admin client -- Go to Administration--->Refresh Server List -->All Domain.
Entire Server list will be updated.
If that also does not help, kindly close notes client and move bookmark.nsf, domadmin.nsf and dommon.nsf out of data directory.
Kindly restart notes client, the files will be created. Kindly check now the Administration server showing against all domino servers.
Regards,
Pramod