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When you run a connection test in MainWP, the result includes an HTTP status code that indicates whether the request succeeded or failed. This reference helps you interpret those codes and understand what action to take.

What You’ll Learn

  • Interpret HTTP status codes from connection tests
  • Identify which codes indicate success vs. failure
  • Understand common causes for specific error codes
  • Determine next steps based on the status code

Prerequisites

  • MainWP Dashboard installed and activated
  • A child site you’re testing connection to

How to Run a Connection Test

Go to MainWP > Sites > Manage Sites, find the site, and click Test Connection from the site’s action menu. The result displays the HTTP status code returned by the child site server.

2xx – Success Codes

These codes indicate the request was received and processed successfully.
CodeStatusDescription
200OKStandard response for successful HTTP requests
201CreatedRequest has been fulfilled; new resource created
202AcceptedRequest accepted, processing pending. Note: On SiteGround, this may indicate a captcha challenge blocking MainWP
203Non-Authoritative InformationRequest processed, information may be from another source
204No ContentRequest processed, no content returned
205Reset ContentRequest processed, no content returned, reset the document view
206Partial ContentPartial resource return due to the request header
207Multi-StatusXML can contain multiple separate responses
208Already ReportedResults previously returned
226IM UsedRequest fulfilled, the response is instance-manipulations
200 OK is the expected result for a successful connection test.

3xx – Redirection Codes

These codes indicate the request was redirected to another location.
CodeStatusDescription
300Multiple ChoicesMultiple options for the resource delivered
301Moved PermanentlyThis and all future requests directed to the given URI
302FoundTemporary response to request found via alternative URI
303See OtherPermanent response to request found via alternative URI
304Not ModifiedResource has not been modified since last requested
305Use ProxyContent located elsewhere, retrieve from there
306ReservedSubsequent requests should use the specified proxy
307Temporary RedirectConnect again to different URI as provided
308Permanent RedirectResumable HTTP requests
Common cause: The child site URL has changed (HTTP to HTTPS, www to non-www, or domain change). Update the site URL in MainWP to match the current address.

4xx – Client Error Codes

These codes indicate the request failed due to a client-side issue.
CodeStatusDescription
400Bad RequestRequest cannot be fulfilled due to bad syntax
401UnauthorizedAuthentication is possible but has failed
402Payment RequiredPayment required, reserved for future use
403ForbiddenServer refuses to respond to the request
404Not FoundRequested resource could not be found
405Method Not AllowedRequest method not supported by that resource
406Not AcceptableContent not acceptable according to the Accept headers
407Proxy Authentication RequiredClient must first authenticate itself with the proxy
408Request TimeoutServer timed out waiting for the request
409ConflictRequest could not be processed because of conflict
410GoneResource is no longer available and will not be available again
411Length RequiredRequest did not specify the length of its content
412Precondition FailedServer does not meet request preconditions
413Request Entity Too LargeRequest is larger than the server is willing or able to process
414Request-URI Too LongURI provided was too long for the server to process
415Unsupported Media TypeServer does not support the media type
416Requested Range Not SatisfiableThe client has asked for unprovable portion of the file
417Expectation FailedServer cannot meet requirements of Expect request-header field
422Unprocessable EntityRequest unable to be followed due to semantic errors
423LockedResource that is being accessed is locked
424Failed DependencyResource that is being accessed is locked
426Upgrade RequiredClient should switch to a different protocol
428Precondition RequiredOrigin server requires the request to be conditional
429Too Many RequestsUser has sent too many requests in a given amount of time
431Request Header Fields Too LargeServer is unwilling to process the request

Common 4xx Codes in MainWP

CodeLikely CauseAction
403Firewall blocking the requestWhitelist your Dashboard IP in the child site’s firewall
404MainWP Child plugin not installed or deactivatedInstall and activate MainWP Child on the child site
415ModSecurity or Imunify360 blocking the requestAdd exclusion rule for your Dashboard IP
429Rate limiting by host or security pluginWait and retry, or whitelist your Dashboard IP

5xx – Server Error Codes

These codes indicate the request failed due to a server-side issue on the child site.
CodeStatusDescription
500Internal Server ErrorGeneric error message
501Not ImplementedServer does not recognize the method or lacks the ability to fulfill
502Bad GatewayServer received an invalid response from the upstream server
503Service UnavailableServer is currently unavailable
504Gateway TimeoutGateway did not receive a response from the upstream server
505HTTP Version Not SupportedServer does not support the HTTP protocol version
506Variant Also NegotiatesContent negotiation for the request results in a circular reference
507Insufficient StorageServer is unable to store the representation
508Loop DetectedServer detected an infinite loop while processing the request
509Bandwidth Limit ExceededHosting bandwidth limit reached
510Not ExtendedFurther extensions to the request are required
511Network Authentication RequiredClient needs to authenticate to gain network access

Common 5xx Codes in MainWP

CodeLikely CauseAction
500PHP error on child siteEnable error logging and check the debug.log file
502Proxy or load balancer issueContact hosting support
503Server overloaded or in maintenanceWait and retry, or contact hosting support
504Request took too longIncrease PHP timeout limits or contact hosting support

Self-Check Checklist

  • Ran connection test and noted the status code
  • Identified whether the code indicates success (2xx) or error (4xx/5xx)
  • Reviewed common causes for the specific code
  • Took appropriate action based on the code meaning