====== TRADER LOGON RESPONSE [35=UCI] ======

The Trader Logon Response message confirms or rejects Trader Logon attempts.

===== Response Indicators =====
  * **Success:** Text (58) = "Success"
  * **Failure:** Text (58) = Error description
  * Failed logon doesn't disconnect FIX session

===== Message Specification =====

**Message Direction:** T4 → Client

^ Tag ^ Field Name ^ Type ^ Req'd ^ Description ^
| | **Message Header** | | Y | MsgType = UCI |
| 553 | UserName | String | Y | T4 Trader username |
| 58 | Text | String | Y | Success or failure reason |
| | **Message Trailer** | | Y | |

===== Sample Messages =====

**Successful Response:**
<code>
8=FIX.4.2|9=100|35=UCI|49=test|56=T4Test|50=T4FIX|52=20150612-15:35:03.725|
553=Trader1|58=Success|10=234|
</code>

**Failed Response (Bad Password):**
<code>
8=FIX.4.2|9=150|35=UCI|49=test|56=T4Test|50=T4FIX|52=20150612-15:34:50.261|
553=Trader1|58=Login failed: most likely incorrect trader and password combination|10=234|
</code>

===== Notes =====
  * Session continues after failed trader logon
  * Master User and other authenticated traders remain connected
  * Trader must have assigned accounts/exchanges for success