You'll need more hive. In general it's a good idea to have around 50 Hive powered up at all times so you have enough resources to interact on the blockchain. This is how Hive gets away with having "no fees" you power up to have resources on chain. Since you're trying to delegate out nearly all of yours it's telling you you don't have enough mana which is resource credits to produce the transaction. You most likely could do 50 though and keep 50 Hive powered up should solve your issue.