web
You’re offline. This is a read only version of the page.
close
Skip to main content

Announcements

No record found.

News and Announcements icon
Community site session details

Community site session details

Session Id :
Dynamics 365 Community / Forums / Customer experience | Sales, Customer Insights,... / D365 Salesforce REST A...
Customer experience | Sales, Customer Insights,...
Suggested Answer

D365 Salesforce REST API error: Unable to tunnel through proxy. Proxy returns "HTTP/1.1 503 Service Unavailable

(0) ShareShare
ReportReport
Posted on by Aratrika 5

Hi,

I am very new to D365 world. I am trying to connect Salesforce to D365 to fetch Opportunity records from D354 to Salesforce. 

I have all setup completed (client ID, secret and REST API class in SF) but when I send REST Request to D365 from Salesforce, I am getting this response 

Unable to tunnel through proxy. Proxy returns "HTTP/1.1 503 Service Unavailable

Something related to whitelist IP address but not sure where to add Salesforce IP address to whitelist in D365.

Thanks in advance. 

I have the same question (0)
  • Suggested answer
    Nya Profile Picture
    Nya 29,064 on at

    Hi,

    Please refer to the following blog.

    Why System.CalloutException: Unable to tunnel through proxy. Proxy returns “HTTP/1.1 503 Service Unavailable” occur (gavan.in)

  • Aratrika Profile Picture
    Aratrika 5 on at

    Hi Nya,

    Thanks for the reply. I have this D365 trial org just practice Salesforce & D365 integration. There shouldn't be any firewall issue since it's in my private network (no VPN involved). Moreover, Salesforce IPs need to whitelist in the D365 network not other way around.

    The other 2 reasons might not be related since I am not using any certificates (just client Id and secret from REST API).

    Hope that make sense to you

  • Suggested answer
    Bipin D365 Profile Picture
    Bipin D365 28,985 Moderator on at

    Hi,

    Would you be able to share your code to troubleshoot this issue?

    I hope you have created the Application User in D365 using Client Id and assigned security role.

    Please mark my answer verified if this is helpful!

    Regards,

    Bipin Kumar

    Follow my Blog: xrmdynamicscrm.wordpress.com/

Under review

Thank you for your reply! To ensure a great experience for everyone, your content is awaiting approval by our Community Managers. Please check back later.

Helpful resources

Quick Links

Introducing the 2026 Season 1 community Super Users

Congratulations to our 2026 Super Stars!

Meet the Microsoft Dynamics 365 Contact Center Champions

We are thrilled to have these Champions in our Community!

Congratulations to the March Top 10 Community Leaders

These are the community rock stars!

Leaderboard > Customer experience | Sales, Customer Insights, CRM

#1
ManoVerse Profile Picture

ManoVerse 151 Super User 2026 Season 1

#2
11manish Profile Picture

11manish 134

#3
Jimmy Passeti Profile Picture

Jimmy Passeti 55 Most Valuable Professional

Last 30 days Overall leaderboard

Featured topics

Hide selecting Contact for potential customer when creating quote

Product updates

Dynamics 365 release plans