Unable to authorize tiktok iPhone problem

Hello zahid45,

Thanks for reaching out to the Apple Support Communities. We understand you are experiencing some issues with an app on your iPhone. We are happy to help provide some guidance.

If an app isn't working as expected on your iPhone, we have some good steps to follow outlined in the following helpful article. Take a look to see if they help:

If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open

If the issue continues, we'd like to ask some additional questions to get a better understanding.

• Does this issue only happen with one app, or multiple apps?
• When did you notice this behavior begin? Was it after any sort of change or update to the iPhone?

Keep us updated on how it goes. We hope this information helps.

Best Regards.