Provide steps to replicate the issue. Is there a reason for the old version of Firefox?

https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

https://support.mozilla.org/en-US/kb/update-firefox-latest-version?cache=no Did you update Firefox to the latest version?

Version 95.0, first offered to Release channel users on December 7, 2021 Version 95.0.1, first offered to Release channel users on December 16, 2021 Version 95.0.2, first offered to Release channel users on December 19, 2021

https://support.mozilla.org/en-US/questions/1359657#answer-1463359 and updated to 95.0. . . . I finally found where the plugin "Widevine Content Decryption Module provided by Google Inc." was not updating to the newest version of December 1, 2021. Ver #4.10.2391.0

cor-el; Make sure you have the latest Widevine version. You can toggle DRM off/on to see if that makes Firefox (re)load DRM components.

• Settings -> General: Play DRM
• https://support.mozilla.org/en-US/kb/enable-drm

You can possibly check the XHR requests in the Browser Console if this doesn't work.

• https://developer.mozilla.org/en-US/docs/Tools/Browser_Console

95.0.2 still got this on aliexpress https://th.aliexpress.com/item/32803933451.html?gatewayAdapt=glo2tha&spm=a2g0o.detail.0.0.14315cc9YOcRHE&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=bb1fee84-095b-42a5-8b78-fba85e2f5dcb&_t=gps-id:pcDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:bb1fee84-095b-42a5-8b78-fba85e2f5dcb,tpp_buckets:668%232846%238116%232002&&pdp_ext_f=%7B%22sceneId%22:%223339%22,%22sku_id%22:%2264323162409%22%7D

screenshot

It works for me. see screenshot

https://th.aliexpress.com/item/1005001708652183.html?spm=a2g0o.productlist.0.0.2b6b442boWwiaQ&algo_pvid=6f4309b5-c230-4dc1-b3d5-ccb93ffca6a6&algo_exp_id=6f4309b5-c230-4dc1-b3d5-ccb93ffca6a6-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000024671259021%22%7D&pdp_pi=-1%3B584.35%3B-1%3B-1%40salePrice%3BUSD%3Bsearch-mainSearch

Can you play this? https://ae-cn.alicdn.com/9f8e1de30350cb41/ej4wKx0Izs3QOjPGr0z/Sh5snz4mZRVQUL7YnIt_339326613436_mp4_264_hd.mp4