Troubleshooting “454 4.7.1 Relay Access Denied” Errors in INKY

Overview

This article helps troubleshoot email delivery failures where a sender receives a relay error such as:

454 4.7.1 Relay access denied

A relay access denied error usually means a mail system attempted to send or relay a message through a server that did not accept the message for that sender, recipient, domain, IP address, connector, or routing path.

This can happen when mail routing is misconfigured, an old routing rule remains in place, a connector or relay is not authorized, or mail is being sent through an unexpected path.

Use this article if you see behavior such as:

• Users receive a bounce-back with 454 4.7.1 Relay access denied
• Messages fail only when sent to a specific domain
• Messages fail after INKY onboarding, migration, or offboarding
• Messages fail after Google Workspace or Microsoft 365 routing changes
• Mail appears to be relaying through INKY unexpectedly
• A customer recently changed routing, connectors, MX records, or SMTP relay settings
• Messages are rejected before they reach the recipient mailbox

What “relay access denied” means

Mail relay occurs when one mail server accepts a message and forwards it to another mail server.

A relay access denied error means the receiving or intermediate server refused to relay the message. This does not always mean the sender, recipient, or message content is blocked. It often means the message is using a relay path that is not authorized.

Common causes include:

• Incorrect Google Workspace routing or SMTP relay settings
• Incorrect Microsoft 365 connector or transport rule configuration
• Mail being sent through an old INKY relay path after routing was changed
• A previous mail security platform or gateway still in the routing path
• A domain-specific routing rule sending mail to the wrong host
• A connector that does not allow the sending IP or domain
• Recipient domain restrictions
• A mismatch between expected sender domain and actual relay path
• Partial onboarding, offboarding, or migration configuration

Step 1: Capture the full bounce-back or error

Start by collecting the full non-delivery report, bounce-back, or SMTP error.

Do not rely only on the short error text. The full bounce-back usually shows which server rejected the message and may identify the failing route.

Capture:

• Full error code and message
• Sender address
• Recipient address
• Subject line
• Date and time sent, including time zone
• Rejecting server or host, if shown
• Sending server or relay host, if shown
• Whether the failure happens for one recipient, one domain, or all recipients
• Whether the issue started after a routing, onboarding, migration, or offboarding change

Step 2: Confirm the direction of mail flow

Determine whether the failed message is:

• Inbound to the customer
• Outbound from the customer
• Internal between customer users
• Sent from a third-party application or device
• Sent through Google Workspace SMTP relay
• Sent through Microsoft 365
• Sent through INKY routing
• Sent through another mail security gateway

This matters because the correct configuration to check depends on where the message entered the mail flow.

Examples:

Step 3: Check whether the issue affects one domain or all mail

Relay errors often reveal whether the problem is broad or domain-specific.

Ask:

• Does this fail for every recipient?
• Does this fail only for one recipient domain?
• Does this fail only for one sender?
• Does this fail only from one application or device?
• Does this fail only after a recent routing or onboarding change?
• Are other customers affected?

If messages fail only when sent to one domain, review domain-specific routing, outbound connectors, or recipient-side rejection.

If all outbound mail fails, review the customer’s outbound mail routing, connector, or SMTP relay configuration.

If all inbound mail fails, review MX records, inbound routing, and gateway configuration.

Step 4: Review Google Workspace SMTP relay and routing

For Google Workspace environments, review the Google Admin console.

Check:

• SMTP relay service settings
• Allowed sender IP addresses
• Allowed authentication method
• Whether only addresses in the customer’s domain are allowed
• Whether the sender is authorized to use the relay
• Routing rules
• Compliance rules
• Inbound gateway settings
• Outbound gateway settings
• Any route pointing to INKY or a previous gateway
• Any old INKY routing after offboarding or migration

Run an Email Log Search for the affected message.

Confirm:

• Whether Google accepted the message
• Whether Google attempted to route it through INKY or another host
• Whether Google rejected the message
• Whether a routing or compliance rule applied
• Which server returned the relay error

Step 5: Review Microsoft 365 connectors and transport rules

For Microsoft 365 environments, review Exchange admin center and Microsoft 365 message trace.

Check:

• Inbound connectors
• Outbound connectors
• Transport rules
• Mail flow rules
• Accepted domains
• Any route pointing to INKY or a previous gateway
• Any old connector left from a prior configuration
• Any connector scoped to a specific domain
• Any connector requiring a certificate or specific sender IP
• Any rule that redirects or relays messages unexpectedly

Run a Message Trace for the affected message.

Confirm:

• Whether Microsoft 365 accepted the message
• Whether Microsoft 365 attempted to route it through INKY or another host
• Whether a connector or transport rule applied
• Whether Microsoft or another server returned the relay error
• Whether the message was rejected before delivery

Step 6: Check for old or partial INKY routing

Relay errors can occur when old routing remains after onboarding, migration, or offboarding.

Review whether the customer recently:

• Installed INKY
• Migrated from Graphus to INKY
• Changed from one INKY routing method to another
• Offboarded from INKY
• Removed or changed connectors
• Changed Google routing rules
• Changed Microsoft 365 transport rules
• Changed MX records
• Added or removed another mail security gateway

Look for:

• Old routes still pointing to INKY
• Old routes pointing to a previous mail security platform
• Duplicate connectors
• Disabled but still-referenced connectors
• Domain-specific rules pointing to the wrong destination
• MX records pointing to an old gateway
• Google routing rules that still send mail to an INKY relay after uninstall

Step 7: Confirm whether mail should be relaying through INKY

Determine whether INKY is expected to be in the mail path for this message.

Check:

• Is this inbound, outbound, or internal mail?
• Is INKY configured to process this type of traffic?
• Is the user or domain included in INKY protection?
• Is the sender or recipient excluded?
• Is this a test message sent before go-live?
• Is the customer partially onboarded or partially offboarded?
• Was routing intentionally changed recently?

If INKY should not be in the path but the logs show the message is still being routed through INKY, update the mail routing, connector, or relay configuration.

If INKY should be in the path, confirm the route and connector are configured as expected.

Step 8: Check application or device SMTP relay

If the message was sent by an application, scanner, website, copier, ticketing system, CRM, billing platform, or other device/service, review SMTP relay configuration.

Check:

• Sending IP address
• Sender address
• SMTP server/host
• Authentication method
• Whether the sender domain is allowed
• Whether the sending IP is allowed
• Whether the application is attempting to relay through Google, Microsoft, INKY, or another host
• Whether the application recently changed IP addresses
• Whether the device is sending as a user or shared mailbox
• Whether MFA or modern authentication changes affected the sender

If the application is relaying through Google Workspace, confirm the Google SMTP relay service allows the source IP and sender domain.

If the application is relaying through Microsoft 365, confirm the connector and relay method are supported and correctly configured.

Step 9: Check recipient-domain-specific failures

If the error occurs only when sending to one recipient domain, review whether a route or connector is scoped to that domain.

Check:

• Domain-specific transport rules
• Google routing rules for that domain
• Microsoft outbound connector scoped to that domain
• Recipient domain rejection reason
• Whether the recipient domain recently changed MX records
• Whether the recipient domain blocks relay attempts from the current route
• Whether the message is being sent through an unexpected intermediate server

Include the recipient domain in any trace or log search.

Step 10: Validate after changes

After correcting routing or relay settings, send a new test message.

Validate:

• Message sends successfully
• No bounce-back is returned
• Message trace or email log shows the expected route
• INKY appears in the path only if expected
• No unexpected quarantine, rejection, or loop occurs
• The recipient receives the message
• INKY banners or processing appear as expected for protected mail

Common causes

Information to gather before contacting support

If the error continues, gather one affected example.

Include:

• Customer or team name
• Customer domain
• Sender address
• Recipient address
• Recipient domain
• Subject line
• Date and time sent, including time zone
• Full bounce-back or non-delivery report
• Full SMTP error text
• Screenshot of the error
• Whether the message is inbound, outbound, internal, or app/device-generated
• Whether the issue affects one recipient, one domain, multiple domains, or all mail
• Whether this started after onboarding, migration, offboarding, or routing changes
• Microsoft 365 Message Trace result or Google Workspace Email Log Search result
• Relevant Microsoft 365 connector or transport rule screenshots
• Relevant Google Workspace SMTP relay or routing screenshots
• MX/routing details, if relevant
• Whether another email security gateway is still in the mail path
• Whether INKY is expected to process this traffic type