If milk has completely stopped you will need to stimulate the flow by expressing a few times a day. You can try latching the baby on but with no milk the baby may not be interested. You can use a breast pump for the same.

gap was one month

if you are lactating, you could feed baby more number of times, or use  breast pump to express milk... it depends on how long you took a break.. also have fenugreek, papaya, drumstick, drumstick leaves, etc.