No, the seller is not obligated to accept your offer even if your offering price is for exactly what he or she is asking because there may be other terms that they don't agree with or they may have received an even better offer from another buyer. The price is only part of the agreement because there could be other terms of your offer that are not acceptable to the seller such as the closing date, possession date, personal property you might have asked for, if you asked the seller to pay your closing costs, did they counter offer, reject your offer or just not respond?