SSN format is xxx-yy-zzzz. 9 digits. There are some non-allowed patterns "000-xx-xxxx" maybe. I used to know -- anyway easy to look them up. 611-12-5539 would be a valid SSN pattern -- I could call somebody and ask them to look it up, but I won't. It's just a random match. Would not mean anything.
Why are you using 6 for August? It should be 8. Mybe you need to use the 08-04-61 format or perhaps 04-08-61. Sometimes the day comes first.