Driver={SQL Native Client};Failover_Partner=tcp:dby;Server=tcp:dbx;
    Database=DB;Uid=user;Pwd=Pwd;Connect Timeout=300;Pooling=false

SqlState:  08S01
NativeError: 10054
MessageText: “TCP Provider: An existing connection was forcibly closed by
    the remote host."

[Microsoft][SQL Native Client][SQL Server]Login failed for user 'user'.

Logon   Error: 18456, Severity: 14, State: 38.
Logon   Login failed for user 'XSUser'. Reason: Failed to open the explicitly
    specified database. [CLIENT: 54.164.196.67]

SQLINTEGER pooling;
DBCRESULT rc = SQLGetEnvAttr(m_henv, SQL_ATTR_CONNECTION_POOLING ,
    &pooling, 0, NULL);

rc is 0, pooling is 0.