Make errors / Config
Function 'displayError' finished with error! Cannot read properties of undefined (reading 'toString')
Cause
The connected service (commonly WordPress) is returning HTML instead of JSON, typically because a security plugin or firewall blocks Make's IPs from the REST API.
Fix
Whitelist Make's published IP ranges in the server firewall and security plugins (Wordfence, Cloudflare). Confirm the REST API is reachable at {site}/wp-json/. Enable Pretty Permalinks in WordPress. If it persists, temporarily disable security plugins to find the blocking rule.
Part of the Automation Error Index — Make errors: browse all.
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