CAPTCHA endless CAPTCHA loops Caused by MAC Randomization — Fix Confirmed

Website, Application, Performance Security
1

What is the name of the domain?

n/a (since the issue occurs across many Cloudflare-protected sites)

What is the error number?

n/a

What is the error message?

None, the Roku devices with MAC randomization enabled result in endless CAPTCHA loops.

What is the issue you’re encountering

Roku devices with MAC randomization enabled, result in endless CAPTCHA loops.

What steps have you taken to resolve the issue?

Disabled MAC address randomization from the Roku network settings. Once a consistent MAC was used, the CAPTCHA loop resolved and access was restored on all Cloudflare-protected sites.

What is the current SSL/TLS setting?

Off

What are the steps to reproduce the issue?

  1. Enable MAC randomization in Roku’s network settings.
  2. Attempt to access a Cloudflare-protected site using the device.
  3. Observe persistent CAPTCHA loading loop or failure to connect.
2

Following up with additional details, as the original post is no longer editable (presumably to protect the daemons from further aexorcism).

:gear: Full breakdown below:

MAC Randomization Causing CAPTCHA Loop on Roku — Confirmed Fix

:magnifying_glass_tilted_left: Issue Summary
Roku devices with MAC address randomization enabled are unable to pass Cloudflare-protected CAPTCHAs. The result is a loading loop (typically with a spinning icon or no visible feedback) that causes sites or services to stall indefinitely.

:television: Affected Devices

  • Roku Express
  • Roku Streaming Stick
  • Roku Ultra
  • Likely others with randomized MAC functionality enabled

:brain: Root Cause
MAC address randomization changes the device’s identity on each connection attempt. Cloudflare interprets these shifting identities as suspicious, treating each attempt like a new visitor or a potential bot — leading to CAPTCHA loops that Roku can’t complete.

:hammer_and_wrench: Confirmed Resolution

  1. On your Roku, navigate to Settings > Network > About
  2. Look for “MAC address” and confirm whether randomization is enabled
  3. If enabled, disable MAC randomization and allow Roku to reconnect using its physical address
  4. Reboot Roku and retry the affected service

:white_check_mark: CAPTCHA loops were immediately resolved once a consistent MAC address was used.

:speaking_head: Final Note
This fix was observed repeatedly across multiple Cloudflare-protected domains. While this isn’t a site-specific issue, it could impact countless users with randomized MAC defaults enabled by firmware updates or factory settings. Might be time for Cloudflare to consider this edge case when assessing device-level challenge behavior.

Let me know if anyone else is seeing the same — or if there’s another daemon lurking in the loop.