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Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →In Chromium-based browsers, GATT operation not permitted is the error text Chromium uses when it maps a Bluetooth GATT GATT_NOT_PERMITTED failure to a JavaScript NotSupportedError. It does not, by itself, reveal why a peripheral rejected your request. First check that your code targets the intended characteristic and that the characteristic supports the read, write, or notification operation you are calling; then verify Web Bluetooth access requirements separately.
What “GATT operation not permitted” means
Web Bluetooth lets a web page connect to and interact with Bluetooth Low Energy (BLE) peripherals. In Chromium’s Blink implementation, the GATT error code GATT_NOT_PERMITTED maps to a NotSupportedError whose message is exactly GATT operation not permitted. (Chromium error mapping.)
This identifies how Chromium reports that particular GATT failure; it does not establish the underlying cause on your device. It is also distinct from errors Chromium maps to messages such as GATT operation not authorized. Do not assume this message alone means the user denied browser permission.
Diagnose the failing operation
- Record the exception and call. Note the exact JavaScript call that fails, the
DOMExceptionname, and its message. Distinguish this error from a similar-looking authorization or permission error. - Verify the service and characteristic UUIDs. Compare the UUIDs in your code with the peripheral’s actual GATT service table or firmware definition. A UUID that resolves to a different characteristic can lead your code to request an operation that does not fit that characteristic’s role.
- Check the characteristic’s properties and intended workflow. Confirm that the characteristic supports the operation you are attempting: reading a value, writing a value, or starting notifications. Do not assume every characteristic supports every operation; check the peripheral’s GATT definition and documentation.
- Reproduce with the intended sequence. Make sure the service and characteristic you retrieve are the ones the peripheral expects for that workflow, and that you call the appropriate operation for the characteristic’s declared properties.
- Collect details if it still fails. Record the peripheral model, service and characteristic UUIDs, characteristic properties, browser and version, operating system, and exact failing call. Those details are needed to investigate a device-specific cause.
Check Web Bluetooth access separately
Even when the GATT target and operation are correct, the page must be able to use Web Bluetooth. The API is limited in browser availability, requires a secure context, is subject to the bluetooth Permissions Policy, and requires explicit user permission. Check the current compatibility information for the browsers and devices you intend to support. These are important API preconditions, but the Chromium GATT_NOT_PERMITTED mapping does not establish that a failed permission check caused this particular message.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
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- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
See MDN’s Web Bluetooth API documentation for the API’s security, permission, and availability notes.
Use reports from other devices as clues, not diagnoses
In a Nordic DevZone thread, a user reported seeing the error while sending data to a BLE UART example. Another participant said a similar write problem was resolved after correcting the characteristic UUID. That makes UUID verification a useful early check, not a guaranteed fix for another peripheral or the original reporter’s issue. (Nordic DevZone discussion.)
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
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Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
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- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Rank #3
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Rank #2
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- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
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