SSL issue with autoscaling

Hi,

First of all, thank you for creating an awesome product.

I'm using Helm chart to install Traefik on my cluster with Let's Encrypt wildcard certificate and autoscaling.
SSL works fine until running a load test (using apache-benchmark), the certificate was being invalidated.
Is there any way to gain persistence certification? I already tried to set persistent.enable is true and accessMode is ReadWriteMany, however, it makes the pods in pending state with the following error:

FailedScheduling 2m13s (x66 over 43m) default-scheduler pod has unbound immediate PersistentVolumeClaims

or

RESOURCE_IN_USE_BY_ANOTHER_RESOURCE

Please help me out. Thank you very much.