---
title: "Grandstream ATA HT801 – Registration Successful but Fax Fails After Move to different location"
slug: "grandstream-ata-ht801-registration-successful-fax-fails-move"
updated: 2026-06-30T07:15:32Z
published: 2026-06-30T07:15:32Z
canonical: "help.8x8.com/grandstream-ata-ht801-registration-successful-fax-fails-move"
---

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# Grandstream ATA HT801 – Registration Successful but Fax Fails After Move to different location

## Objective

Provide guidance for diagnosing and resolving fax failures on a **Grandstream ATA HT801** that is registered and online but experiences inbound/outbound fax issues after relocation

## Applies To

- Grandstream HT801 ATA
- Analog fax devices (e.g., Canon imageCLASS MF615iF)
- 8x8 PBX extensions configured for fax
- Scenarios involving device relocation or environment change

## Procedure

#### **1. Extension & ATA Configuration Review**

Verified extension **xxxx** configuration:

- ✅ Primary DID correctly assigned: **xxxxxxxxxxx**
- ✅ Codec: **G.711u**
- ✅ Fax Mode: **T.38 enabled**
- ✅ Call Waiting: **Disabled**
- ✅ Dial Plan: **NANP-INTERNATIONAL (or whatever service needed)**
- ✅ No restrictions applied
- ✅ ATA registered and online

Result: **No configuration issues identified**

#### **2. Root Cause Identification**

Further review identified:

- **Call forwarding rules were not configured**
- Extension was expected to forward on **No Answer / Busy (rejected)**, but forwarding was unset
- Extension profile contained **over 100 voicemail entries**, exceeding recommended limits and needed deletion

These conditions caused unpredictable call handling, directly impacting fax call completion.

## Additional Information

- Fax issues can be caused by **PBX-level call handling**, even when ATA and codecs are correct
- Excessive voicemail entries can affect call processing
- Always review:
  - Call forwarding rules
  - VM count on fax extensions
  - Extension behavior after relocation