Potty training

Mama

I need serious help…. We’ve been introducing the potty and potty training since around 18 months and she still refuses to let me know when she needs to go!

She will use it 100% of the time no accidents if she is without underwear or a pull up but as soon as something is on her she will not go to the potty!

What can I do??? We’ve rewarded her, stopped rewards, started sending her to time out and nothing changes anything