Configuration/setup required for 3-part naming for SQL

What are the requirements to enable 3-part naming in SQL? Google was not my friend.

We're on 7.4 and have DB2 Multisystem (which I seem to recall was a requirement) on all our partitions. User ID and password are the same on all partitions.

CONNECT TO QASYS1 USER DBALE USING 'the_correct_password'
^ returns SQ30061 "Relational database QASYS1 not found." Which is weird, because WRKRDBDIRE clearly shows QASYS1 (see below)

Using either:
1) select * from QASYS1.DBALELIB.TESTFILE
or 2) CONNECT TO QASYS1 USER DBALE USING 'a_wrong_password'
results in:

Message ID . . . . . . : SQ30082 Severity . . . . . . . : 30
Message type . . . . . : Diagnostic

Message . . . . : Authorization failure on distributed database connection
attempt.
Cause . . . . . : A connection attempt failed with reason code 17.
17 -- The security mechanism requested by the client is not supported or
allowed at the server. See recovery information below.
Recovery . . . : A common cause for reason code 17
is that the server requires a password, but because the client does not have
a password to send, sends only a user ID. Or, the server requires an
encrypted password and the client did not send an encrypted password. A
password can be supplied by the user in two ways:
1 -- By using the USER ... USING ... clause on the SQL CONNECT statement, or
2 -- By using the ADDSVRAUTE CL command to add a server authorization entry
for the remote server under the user's profile. The server name (DRDA RDB
NAME) must be entered in upper case.
The DRDA server can be configured with the CHGDDMTCPA CL command to not
require a password, or to not require an encrypted password.

DSPSVRAUTE, on both the source and target partition, shows my user profile with Server=*ANY and Password Stored=*YES.

Display Relational Database Entry Detail
Relational database . . . . . . : QASYS1
Remote location:
Remote location . . . . . . . : QASYS1
Type . . . . . . . . . . . . : *IP
Port number or service name . : *DRDA
Remote authentication method:
Preferred method . . . . . . : *USRENCPWD
Allow lower authentication . : *ALWLOWER
Secure connection . . . . . . : *NONE
Encryption algorithm . . . . . : *DES
Relational database type . . . . : *REMOTE
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