Hi and welcome do devnet,
found some issues in your regexp
DATE:(\\\d{1,2}):(\\\d) should be DATE:(\\\d{1,2}):(\\\d{2})
(\\\d{1,2})\\/(\\\d)\\/(\\\d{2,4}) should be (\\\d{1,2})\\/(\\\d{1,2})\\/(\\\d{2,4})
in your regexp SEND-ID follows AUTH but in your string is not true
BTW a simple solution to make debug easier could be to split the string in lines and process a line at time