Hello! I'm sorry to hear that you're having trouble with your Vivo Y91. Here are some possible solutions for your problem:
1. Try using a different USB cable or USB port on your computer to see if that helps with the detection issue.
2. Make sure that USB debugging is enabled on your phone. To do this, go to Settings > Developer Options > USB Debugging and toggle the switch to "On".
3. Install the appropriate USB drivers for your Vivo Y91 on your computer. You can download them from the Vivo website or a third-party website.
4. If none of the above solutions work, try using a different computer to see if the issue is with your computer or the phone.
If you're still having trouble, it may be best to bring your phone to a professional technician or the manufacturer for further assistance.
