accuracy_hat_arc不超过0.6，损失处于1.5

您好，我使用arcface训练四分类任务，最后的训练结果：
Iteration 285400(1.51479 iter/s,132.031s/200 iters),loss=1.58242
Train net output #0:accuracy_hat=1
Train net output #1:accuracy_hat_arc=0.4375
Train net output #2:loss_hat=1.58242(*1 = 1.58242 loss)

accuracy_hat_arc的精确度始终不能高于0.6，
loss_hat损失始终处于1.5多，不收敛

请问有谁遇到这个问题，或有解决思路？江湖救急，谢谢了