Behavior
When loading Box content in Salesforce via the Box Embed Lightning component on a record page, app page, Screen Flow, or other custom embed widget, a connection error may appear and Box content fails to load.
Two common error messages are:
a. "Unable to resolve the server's DNS address"
b. "{0}{1}app.box.com's server IP address could not be found"
Cause
a. "Unable to resolve the server's DNS address"
The Box Enterprise Sub-Domain on the Box Settings page is incorrect. The value must be only the subdomain portion of your Box URL—not the full domain.
b. "Server IP address could not be found"
The Box enterprise subdomain is not fully applied to the integration. The browser tries to connect using a placeholder domain (such as {0}{1}app.box.com) instead of your actual Box URL. This can occur when the subdomain appears correct in Box Settings but the underlying org configuration was not refreshed.
Resolution
- Confirm the Box Enterprise Sub-Domain in Box Settings → Content.
- Enter only
<companysubdomain>(for example,cloudif your Box URL ishttps://cloud.app.box.com). - Do not enter a full URL such as:
<companysubdomain.app.box.com><companysubdomain.com><www.companysubdomain.com>
- Save the setting and retry the affected feature.
- Enter only
- If the error persists—or the message includes
{0}{1}app.box.com—reconnect the Box Service Account in Box Settings → Authentication.- Click Reconnect (or connect if not already connected).
- This refreshes the org-level Box connection settings used by embed features.
- Retry the affected feature after reconnection completes.
If the issue continues after both steps, contact Box Support and include the exact error message as well as the network logs from the browser.