WTF is Going On? HR Acting Strange After I Asked for More Pay

Hey folks, I got selected for a Manager role, submitted my documents, and we discussed salary. They offered ₹11 LPA, but I expected ₹15 LPA. I told them my absolute minimum is ₹12 LPA, and since then, HR says they need to check with the Head of Marketing, who now "needs time to think." The tone of the HR's voice lacked the enthusiasm which was there initially.

It’s been 4 days with no proper response. Are they reconsidering my offer, stalling to push a lower salary, or is this normal? Should I follow up or take this as a red flag? Would love some advice!