Hello, I have dovecot director on one server and today I notice 146 times the same problem. Log below. I try restart dovecot and mysql (auth-db backend) but with no effect. Please help. If any other information is needed I send it. My dovecot version is 2.1.15. 2014-03-26T16:15:28+01:00 r1 dovecot: auth: Fatal: master: service(auth): child 9883 killed with signal 6 (core dumps disabled) 2014-03-26T16:15:43+01:00 r1 dovecot: auth: Panic: file passdb-blocking.c: line 124 (passdb_blocking_lookup_credentials): assertion failed: (auth_stream_is_empty(request->extra_fields) || request->master_user != NULL) 2014-03-26T16:15:43+01:00 r1 dovecot: auth: Error: Raw backtrace: /usr/lib64/dovecot/libdovecot.so.0(+0x4469a) [0x7fdb06e1469a] -> /usr/lib64/dovecot/libdovecot.so.0(+0x446de) [0x7fdb06e146de] -> /usr/lib64/dovecot/libdovecot.so.0(+0x1c0ea) [0x7fdb06dec0ea] -> dovecot/auth [34 wait, 1 passdb, 0 userdb](passdb_blocking_verify_plain+0) [0x41f593] -> dovecot/auth [34 wait, 1 passdb, 0 userdb](auth_request_lookup_credentials+0x104) [0x413c41] -> dovecot/auth [34 wait, 1 passdb, 0 userdb]() [0x41c202] -> dovecot/auth [34 wait, 1 passdb, 0 userdb]() [0x4139e6] -> dovecot/auth [34 wait, 1 passdb, 0 userdb](auth_request_lookup_credentials_callback+0x6a) [0x413abb] -> dovecot/auth [34 wait, 1 passdb, 0 userdb](passdb_handle_credentials+0x50) [0x41f389] -> dovecot/auth [34 wait, 1 passdb, 0 userdb]() [0x41f82e] -> dovecot/auth [34 wait, 1 passdb, 0 userdb]() [0x41798f] -> /usr/lib64/dovecot/libdovecot.so.0(io_loop_call_io+0x27) [0x7fdb06e1f68c] -> /usr/lib64/dovecot/libdovecot.so.0(io_loop_handler_run+0x9e) [0x7fdb06e204ee] -> /usr/lib64/dovecot/libdovecot.so.0(io_loop_run+0x27) [0x7fdb06e1f645] -> /usr/lib64/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7fdb06e0d348] -> dovecot/auth [34 wait, 1 passdb, 0 userdb](main+0x380) [0x41a396] -> /lib64/libc.so.6(__libc_start_main+0xfd) [0x7fdb062ced2d] -> dovecot/auth [34 wait, 1 passdb, 0 userdb]() [0x40ced9] 2014-03-26T16:15:43+01:00 r1 dovecot: auth: Fatal: master: service(auth): child 18546 killed with signal 6 (core dumps disabled)