Earbuds will not connect to an iPhone if you are having Bluetooth problems. You must have the devices in close proximity to each other and make sure they are fully charged. Once they are connected, you should stay within 30 feet of the connected device.
JLab earbuds might not produce sound due to several reasons: accidental selection of audio presets, some of which may mute or significantly lower the volume; malfunctions or obstructions in the detection sensors, making them erroneously pause or stop playback; and interference from nearby magnetic fields or electronic devices, disrupting play and connectivity functions.
A potential cause of low volume in earbuds could be the presence of earwax or other debris in the speaker of the earbud. A solution to this issue is to gently clean the earbuds using a dry cotton swab or a brush with soft bristles, ensuring not to damage the speaker in the process.