What are requotes? and how to prevent it?

Well, requotes are not good thing, when you are watching market and market is in your favor, and you want to open an order according to market trend, but the market is fast, so you will face an error or requotes. it means that the price has been changed and you will have to requote your order with new price, and when you press ok to that price then you see another requote error. So, if you want to save yourself from requotes then open pending order or if you want instant execution of order then click on the small box at the bottom of order window, you can see that in the picture below:

Here you can see the option "Enable maximum deviation from quoted price". click on that button will open the option "Maximum deviation" below. Here you can set how much pips do you want to set. There is 0 to 10 pips in that option, if you want to use it then ideal is 3 pips. It will prevent requotes and when you open an order in running market then it will place your order within 3 pips difference. 

Other thing is pending order. In the "type" dialog box, you can find three options, one is instant execution, second is pending order and third one is modify order. Click on pending order, you will find as below:

Here you can see options for pending order. use your desired option and prevent requotes.