Could be that the cords’ plugs just aren't fitting into the jack properly. I’ve seen this issue with 1/8” jacks and plugs for many years…before even iPods were out. Using a blade to trim away a bit of the plastic at the base of the plug worked in some cases.
Well, the only problem is the Aux chords I am using I have been using for years.
IOS 10.3 has code in it to disable non MFI (Made For iPhone) accessories. Perhaps your aux cord is not certified.
You may have jumped from 10.2.1 or lower to 11, thus rendering your aux cord useless.
Do you get an 'Accessory not Supported' message?
See, this is the ******** I have been concerned about. I don’t know which version I upgraded from but I did not miss any upgrades and did them as they came up.
An Aux chord is an aux chord to me. It shouldn’t have to be ‘Certified’ to use it on a damn iPhone. I love the iPhone but when crap like this goes on it makes me want to switch. Does Apple even sell an aux chord??
What can we, as consumers, do to get them to change it back??