The admin password is not your passphrase, not your account id, and not your public key, it is something else, read on.
When connecting to a remote node using the API, there are certain operations which are restricted by default unless the submitted adminPassword parameter matches the value of the the remote node admin password.
Setup the admin password in the remote node nxt.properties file:
# Password that should be provided when executing protected (administrative) API requests.
# Please choose a decent password here. Preferably, use a password generator.
# Password protection is disabled and password is not needed when the API server only listens on the localhost interface, i.e. when nxt.apiServerHost=127.0.0.1.
The same value specified in nxt.adminPassword should be submitted when calling any API which accepts adminPassword as parameter.
When loading the wallet from a remote node enter this value in the account settings page "Administrator Password" field.
The admin password is required for the following operations (partial list)
1. For any query API such as getBlockchainTransactions to return more than 100 records
2. get and stop APIs for forging, bundling, funding monitor and shuffler
3. Access to the /dbshell page to execute SQL queries
4. Various administrative APIs
API response errors and their meaning:
"Administrator's password is not configured. Please set nxt.adminPassword" - you need to configure the admin password on the remote node.
"adminPassword not specified" - password is configured on the remote node but is not specified by the API call
"Incorrect adminPassword" - the specified password does not match the remote node password
"Too many incorrect admin password attempts from ..." - too many incorrect password attempts, wait for an hour or restart the remote node