When Grahtos had first launched his attack, the man was super confident that the offensive would be an instant grand slam.
And it was reasonable to assume so given that he had caught the enemy completely unaware, with many of the mercenaries caught literally out of their pants.
Hence Grahtos was of the mind that he would have to 'just kick in the door and the whole thing would come tumbling down.'
Thus it was very frustrating for him to find himself bogged down right at the start of the offensive, unable to proceed further.
And when inquired about it, the reason quickly revealed itself as retold by a runner,
"Commander, the troops at the front are refusing to advance! No matter how much we try to urge them they are like mules, refusing to budge!"
Yes.