@ilnar.aliullov
We’re sorry to hear you’re having trouble.
Is the OpenGL enumerant 0x84BF
something you are using from a custom extension?
If not, can you provide further info about the environment you are running (iOS version, device, etc).
Are you able to ZIP up an Xcode project that demonstrates the issue, post it to a site like Dropbox, and then post a link here? We can then have a look at it directly. If your project is not something you want to post in public, once you have posted the ZIP to a site like Dropbox, you can email the private link to support@metalgl.com.
…Bill