Here are a few common reasons for Limit Orders not being filled.
The exact limit order price target might not have been reached.
There might be a difference in the the price of your limit order and the current market price. The chance of your order being filled increases as the market price gets closer to your order’s price.
The limit order price may also have been briefly reached on a dex that has not integrated KyberSwap limit orders as a liquidity source, but only swaps on dexes that have integrated KyberSwap limit orders will be able to fill your limit order.
The order might not have been profitable for a taker
Takers must consider the order's size, gas fees, and personal profit margin before deciding to fill your order. Furthermore, some takers might only fill part of your limit order, and then seek out more profitable orders elsewhere.
The order involves tokens that have low trading volumes
Orders that involve exotic tokens or token pairs may have fewer takers to fill the order.
The order involves tokens that have non-standard logic
The limit order feature was designed with the most commonly traded standard ERC20 tokens in mind. Some tokens have non-standard logic and features (e.g. fee-on-transfer, treasury lockup) which may interfere with the correct operation of the limit order feature. Please do your own research on unfamiliar coins before trading them.