Sounds like a nursing strike -- a selective one. One of the reason why a baby goes on this strike is because breastfeeding has been on a strict schedule, timed feedings, or regular interruptions. Because baby is so used to the bottle in the day when you are at work, it is imprinted in his routine that he only takes the breast at night.
Because your baby seems to accept the breast during bedtime, you can try to offer when baby is in a relaxed or sleepy state. Try breastfeeding while baby naps and use feeding positions baby likes best. When you are not feeding, hold baby against your skin, and stay that way as much as possible. This is soothing to both of you, and the hormones released from this skin-to-skin bonding will make baby more open to breastfeeding.
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