The remote name could not be resolved: 'api-3t.sandbox.paypal.com'

Question

I am using paypal NVP api in an ecommerce website. It was working fine before but now it is throwing "System.Net.WebException: The remote name could not be resolved: 'api-3t.sandbox.paypal.com'" Exception. I also tried api.sandbox.paypal.com but no luck. Any ideas?

Thanks

Update : Same codes works if my client runs it from his system.

Answer 1

This is a DNS problem, or at least, that's what the exception points to. The machine that is running your code, and failing, is not able to resolve the hostname 'api-3t.sandbox.paypal.com' to an IP address.

Potential problems, in order of likelyhood:

• Your machine does not have a DNS server configured properly.
• Your machine is using a DNS server that filters queries.
  • This is common in corporate environments; filtering is done to try to stop malware from working.
• Your machine does have a DNS server configured, however, that server may refuse to perform recursive querys
  • This is typical of 'authoritative-only' DNS servers.
• Your code is somehow misusing the local DNS query API.
• Paypal's DNS servers are broken.

You could fire up a command prompt on that machine and see if normal DNS resolution works:

c:\>nslookup api-3t.sandbox.paypal.com
Server:  google-public-dns-a.google.com.
Address:  8.8.8.8

Non-authoritative answer:
Name:    api-3t.sandbox.paypal.com
Address:  173.0.82.83

If you want to try to bypass your institution's DNS server for testing, you can reconfigure your computer to use Google's public DNS server, 8.8.8.8.