2573806 - Application server cannot connect (DB-Connect 000256)

Database is running.
Work processes can not connect to the database:

In work process traces, one can see error:
C  *** ERROR =>   execute(), rc=1, rcSQL=7
 [dbsdbsql.cpp 1330]
C  *** ERROR => Get session info failed : rc=7
 [dbhdbsql.cpp 1761]
C  SQLCODE    : 7
C  SQLERRTEXT : feature not supported: cannot select user-defined type: line 1 col 62 (at pos 61)
C  SQL COMMAND: SELECT CURRENT_USER, CURRENT_SCHEMA, CURRENT_CONNECTION FROM DUMMY;
C  Disconnecting from connection 0 ...
C  Now I'm disconnected from HDB
B  ***LOG BY2=> sql error 7      performing CON [dbsh         1262]
B  ***LOG BY0=> feature not supported: cannot select user-defined type: line 1 col 62 (at pos 61) [dbsh         1262]
B  ***LOG BY2=> sql error 7      performing CON [dblink       647]
B  ***LOG BY0=> feature not supported: cannot select user-defined type: line 1 col 62 (at pos 61) [dblink       647]
M  ***LOG R19=> ThDbConnect, db_connect ( DB-Connect 000256) [thDatabase.c 86]
M
M Mon Nov 20 13:22:36 2017
M  in_ThErrHandle: 1
M  *** ERROR => ThInit: db_connect (step TH_INIT, thRc ERROR-DB-CONNECT_ERROR, action STOP_WP, level 1) [thxxhead.c   2535]

Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.   

• SAP HANA, platform edition 1.0
• SAP HANA, platform edition 2.0

reserved, dummy, DB-CONNECT_ERROR, sql error 7, performing CON, 000256 , KBA , HAN-DB , SAP HANA Database , Problem