Does the front panel have a microphone slot and a headphone one or is it trying some kind of detection? I would normally expect two ports or just headphones but there are some that go in for fun stuff.
Many drivers will still have an attempt at an idiot check in there though (usually some kind of resistance check or what pins are connected to what check) and if it false positive then I would wonder if something has gone wrong inside the speaker (presumably the right one or electronics supporting it but could still be something else, or even the port itself if the spring has broken*) such that it trips detection.
*if you have ever had a phone or something stay in headphones in mode and noted the spring is not working as it should when you do plug in a 3.5mm then same idea. Here though it would presumably detect the fourth ring connector that microphones often have as doing something different to what it expects of conventional speakers where 3 is probably the order of the day.
At this point I would try another set of speakers (with another cable) or headphones if you have them as that will help narrow things down to computer vs speakers (or cable to them). You can try plugging the speakers into another device if you want but if said other device does not have any detection it might not reveal much and while speaker setups are usually fairly robust the first clue something is wrong might be something starting to release the magic smoke. Have you wiggled the cable a bit as well? I rarely see them or the ports inside computers fail in such a manner but have had it happen before and it is more common in other devices.
After this then it is time to bust out the multimeter, probably open the speakers up and see if there is anything untoward happening.
It is probably not a driver issue but ignoring warnings of magic smoke then some things might offer the option to disable idiot check/attempt to automatically detect new insertions which might work for this.
