501 : Base 64 decode failed for ADAT data: error

Explanation

The server received an ADAT command containing authentication data but was unable to decode the authentication data.

error can be one of the following values:
1
Bad character in encoding: An invalid character was received from the server as part of a base 64 encoded string. The valid characters in a base 64 encoded string are the letters A–Z, the letters a–z, the numbers 0–9, the plus sign (+), and the forward slash (⁄).
2
Encoding not properly padded: An invalid base 64 encoded string was received from the server. The string was not padded with equal signs to extend the length of the string to a multiple of four characters.
3
Decoded number of bits not a multiple of 8: An invalid base 64 encoded string was received from the server. The string was unable to be decoded because it did not decode into a multiple of eight bits.

System action

Authentication negotiation fails. FTP continues.

User response

Contact the system programmer of the client to determine why the authentication data was not properly base 64 encoded.

System programmer response

None.