2555159 - Shadow instance on Windows cannot connect to SAP HANA database during SAP Upgrade

During the upgrade of an SAP system based on SAP NetWeaver, the connection from the shadow instance to the HANA database fails with the following error:

C  Try to connect via secure store (UPGSHDKEY) on connection 0 ...
C  *** ERROR => Connect to database failed, rc=1, rcSQL=10
 [dbhdbsql.cpp 419]
C  SQLCODE    : 10
C  SQLERRTEXT :authentication failed
B  ***LOG BY2=> sql error 10     performing CON [dbsh         1262]
B  ***LOG BY0=>authentication failed [dbsh         1262]
B  ***LOG BY2=> sql error 10     performing CON [dblink       644]
B  ***LOG BY0=>authentication failed [dblink       644]
M  ***LOG R19=> ThDbConnect, db_connect ( DB-Connect 000256) [thDatabase.c 86]
M  in_ThErrHandle: 1
M  *** ERROR => ThInit: db_connect (step TH_INIT, thRc ERROR-DB-CONNECT_ERROR, action STOP_WP, level 1) [thxxhead.c   2551]

However, using the <sid>adm user to test test the connection with hdbsql -u or hdbsql -U, using the shadow instance user or key, it works.

• SAP HANA, platform edition;
• SAP NetWeaver;
• Windows Server;

shadow, shd, hdb, keystore, userstore, sidadm, default, No mapping between account names and security IDs was done , KBA , HAN-DB-CLI , SAP HANA Clients (JDBC, ODBC) , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem