Unable to acquire further connections in AWS S3 Async client after failure

Question

Using V2 of the Java AWS SDK, with V2 of the netty nio client, we hit a scenario where we DDOS our application and then get the error:

"Caused by: java.lang.Throwable: Acquire operation took longer than the configured maximum time. This indicates that a request cannot get a connection from the pool within the specified maximum time. This can be due to high request rate.
Consider taking any of the following actions to mitigate the issue: increase max connections, increase acquire timeout, or slowing the request rate.
Increasing the max connections can increase client throughput (unless the network interface is already fully utilized), but can eventually start to hit operation system limitations on the number of file descriptors used by the process. If you already are fully utilizing your network interface or cannot further increase your connection count, increasing the acquire timeout gives extra time for requests to acquire a connection before timing out. If the connections doesn't free up, the subsequent requests will still timeout.
If the above mechanisms are not able to fix the issue, try smoothing out your requests so that large traffic bursts cannot overload the client, being more efficient with the number of times you need to call AWS, or by increasing the number of hosts sending requests."

Tuning aside - why can our application not recover from this? Every subsequent request, even hours later after the event are still throwing the exception. The only way to recover is to restart the application, which feels wrong.

thank you