If you're skipping has stopped working then it means you have YouTube Enhancer.

Read the dev comments and install the version of YouTube Enhancer that doesn't eff up SB.

On Android it doesn't seem to actually skip the sponsors but it highlights them, the extension also causes the full screen video to flip orientation to vertical when interacting with the video. Works great on desktop though

I like thise addons. I like Mozilla, fundation, and Brother Firefox. Good job

YouTube update caused the extension to not skip segments anymore. Needs a fix.

Update: Fixed, Firefox & Enhancer for YouTube had received an update, thus this extension also works again.

Great concept and I have been using it for quite some time now but a few days ago it just stopped skipping segments. And no, my settings are not wrong. It doesn't even promp that there is a segment, they're just shown in the progress bar and nothing more.

The latest 2.0.128 update to Youtube Enhancer seems to conflict with SponsorBlock as the latter no longer skips skippable segments in videos when 2.0.128 is installed. I installed the previous 2.0.126.1 and this fixed it. Just posting here in case someone who uses both sees that SponsorBlock no longer works and thinks it's SponsorBlock's fault, it's not.

This is the single best add-on for YouTube. I just had to write a review to express how incredible it is. There are so many videos/channels that I stopped watching because I was tired of all the sponsored segments interrupting everything. I would have to scrub through them, tediously. Now, it just skips right over them no problem. Truly amazing!

Being able to consume media without the fluff of sponsors, being reminded to sub, intros and outros built into the video makes this a special addon, especially when you can do it on normal videos and music videos. Not only is this a crowdsourced extension that everyone contributes to, but you can too! If you see a video not have the sponsorblock added, please contribute if it needs it!
It's fantastic at what it does and I cannot recommend it any further than the highest praise. Make sure to check out this developer's work. Very smart, very helpful and very user-friendly!

edit: removed my reference to the titles since that's from a different extension by the same developer

I just installed this and the difference is night and day. the sponsor cuts are seamless and make the viewing experience so much better. Thank you so much for developing this extension!