Frequent No Such Host is Known Errors when Retrieving Text from Storage Bucket Files

News Knowledge Base
,
1

Why do I get frequent 'No Such Host known' error when trying to retrieve information from UiPath Orchestrator Storage Buckets?

Issue

When trying to retrieve text from an UiPath Orchestrator Storage Bucket, 'No Such Host known' error might occur. An error message like the one described below is seen very frequently, causing the automation to fail:

No such host is known. (crpapaidorch0eus2stg.blob.core.windows.net:443)

Cause

This issue is mainly related to DNS name resolution. If a DNS server is unable to resolve the name to the proper IP address, this error is encountered.

Troubleshooting the issue

  • Run a nslookup command for 10 to 15 minutes on command prompt to check if the issue is with the DNS server. The below cmd.exe command writes an output to nslookup_output.txt file. Replace crpapaidorch0eus2stg.blob.core.windows.net with the host name which is failing to resolve
for /l %i in () do (nslookup crpapaidorch0eus2stg.blob.core.windows.net >> nslookup_output.txt & timeout /t 2)

This script is a Windows Batch command loop, and here's what it does step by step:

  1. for /l %i in (): Sets up an infinite loop using the FOR command. Without specified parameters (e.g., start, step, and end), the script will execute endlessly, meaning it will repeatedly run the commands inside the parentheses.

  2. nslookup crpapaidorch0eus2stg.blob.core.windows.net >> nslookup_output.txt: Executes the nslookup command to query the DNS information for the domain crpapaidorch0eus2stg.blob.core.windows.net.

    • The >> nslookup_output.txt part appends the result of each query to the file named nslookup_output.txt. If the file doesn't exist, it will be created.

  3. timeout /t 2: Pauses the script for 2 seconds between each iteration. This is useful for spacing out the DNS queries to avoid overwhelming the server or network.

Essentially, the script continuously performs DNS queries for the specified domain and logs the results into a file (nslookup_output.txt) with a 2-second interval between each query.

This kind of script might be used for:

  • Monitoring changes in DNS records over time.

  • Debugging or testing connectivity to the domain.

  • Capturing and analyzing DNS responses for troubleshooting.

If you intend to use this script, be cautious about running it indefinitely, as it could create an excessively large output file or put unnecessary strain on the network or the queried server.

  • DNS server should give an output like below

Server: xxx

Address: xxx

Name: blob.iad01prdstr06a.store.core.windows.net

Address: 20.60.220.225

Aliases: crpapaidorch0eus2stg.blob.core.windows.net

  • If there is a problem with DNS name resolution, you will see error as below

DNS request timed out.
timeout was 2 seconds.

kb-0EMPa00000GahEv.png455×156 3.7 KB

Resolution

Raise the issue with the internal DNS Administrator team to fix the issue.