Status of transaction in wallet: ‘Not in memory pool’

Everytime I try to to make a transaction from my wallet to the exchange, it says status: unconfirmed and ‘not in memory pool’ plz can someone help me figure this out. What am I doing wrong and what do I need to do. I have set the fee as 0.09LTC and it doesn’t let me go any higher than 0.1 LTC. I’m willing to pay higher but it’s not letting me. I’ve been waiting for 4+ hours and still no result. Plz someone help. Thanks