Re-interview for H1B VISA

hi i attended for H1 VISA interview on June 25th and got 221G, and they told with in 2-4 weeks we will get back on your case.
On July 11th i got call from HYD consulate and asked me come for Re-interview for H1B VISA.
can you please share why do they call me again? is anyone faced this type of situation earlier?
i asked her about do i need to carry any documents, she told not needed…

thank you in advance!!!