Could not delete or detach volume

I have 6 EBS "in-use" volumes not attached to any instances. And I can`t delete, detach them or do something with that.
I have looked at logs of my application and found out that at the same time when volumes were created there were responses from AWS with InternalError codes.

First of all, I decided to add a handler for these errors in my app. It helps to improve the situation but does not solve the root cause. I can`t understand the causes of these errors.

My second difficulty is that I can`t remove volumes although no instance uses them.

Edited by: hashted on Apr 23, 2020 2:12 PM