ResponseError('too many 500 error responses')

> ### `az feedback` auto-generates most of the information requested below, as of CLI version 2.10.1
**Describe the bug**

When I trying delete board from project on command line with AZ CLI:
`$ az boards area project delete --path [board_path] --project [project_name] --org [ORG_URL] --yes`

I've got an error bellow:

`request failed: Error occurred in request., RetryError: HTTPSConnectionPool(host='dev.azure.com', port=443): Max retries exceeded with url: /EX93137/demo-project-automated/_apis/wit/classificationNodes/areas/ (Caused by ResponseError('too many 500 error responses',))`

**To Reproduce**
Run command:
`$ az boards area project delete --path [board_path] --project [project_name] --org [ORG_URL] --yes`
on terminal

**Expected behavior**
The selected board being deleted from project

**Environment summary**
```
azure-cli 2.10.1

command-modules-nspkg 2.0.3
core 2.10.1
nspkg 3.0.4
telemetry 1.0.4

Extensions:
azure-devops 0.18.0

Python location '/opt/az/bin/python3'
Extensions directory '/home/ex93137/.azure/cliextensions'

Python (Linux) 3.6.10 (default, Aug 6 2020, 08:50:28)
[GCC 9.2.1 20191008]
```