First time, app run normally but if you kill the app and run it again, app crash immediately. If restart iphone, app can run only first time same as above. Developed from Visual Studio Xamarin What is this log told me ? Hardware Model: iPhone8,4 Process: XXXXXXX.iOS [393] Path: /private/var/containers/Bundle/Application/9CF84154-0C87-49C4-85E9-1D495D323ED9/XXXXXXX.iOS.app/XXXXXXX.iOS Identifier: com.xx.xxxxx Version: 1.0 (1.15) AppStoreTools: 12E506 AppVariant: 1:iPhone8,4:14 Beta: YES Code Type: ARM-64 (Native) Role: Foreground Parent Process: launchd [1] Coalition: com.xx.xxxxx [397] Date/Time: 2021-08-12 20:06:00.5105 +0700 Launch Time: 2021-08-12 20:06:00.3810 +0700 OS Version: iPhone OS 15.0 (19A5318f) Release Type: Beta Baseband Version: 11.00.00 Report Version: 104 Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Triggered by Thread: 0 Last Exception Backtrace: 0 CoreFoundation 0x181b4d314 0x181abb000 + 598804 1 libobjc.A.dylib 0x199214748 0x199200000 + 83784 2 CoreFoundation 0x181c1ca64 0x181abb000 + 1448548 3 CoreFoundation 0x181ae6abc 0x181abb000 + 178876 4 CoreFoundation 0x181ae5d2c 0x181abb000 + 175404 5 XXXXXXX.iOS 0x1035088e8 0x102560000 + 16419048 6 XXXXXXX.iOS 0x1034baf10 0x102560000 + 16101136 7 XXXXXXX.iOS 0x1034badc4 0x102560000 + 16100804 8 XXXXXXX.iOS 0x1034ba7f8 0x102560000 + 16099320 9 XXXXXXX.iOS 0x103495458 0x102560000 + 15946840 10 XXXXXXX.iOS 0x103662de4 0x102560000 + 17837540 11 XXXXXXX.iOS 0x102594934 0x102560000 + 215348 12 XXXXXXX.iOS 0x102902010 0x102560000 + 3809296 13 XXXXXXX.iOS 0x103c88118 0x102560000 + 24281368 14 XXXXXXX.iOS 0x103d1ebc0 0x102560000 + 24898496 15 XXXXXXX.iOS 0x103d220b0 0x102560000 + 24912048 16 XXXXXXX.iOS 0x1025641d0 0x102560000 + 16848 17 XXXXXXX.iOS 0x102565438 0x102560000 + 21560 18 UIKitCore 0x18409bdac 0x183e1c000 + 2620844 19 XXXXXXX.iOS 0x103507ee8 0x102560000 + 16416488 20 XXXXXXX.iOS 0x10346dff0 0x102560000 + 15785968 21 XXXXXXX.iOS 0x10346df74 0x102560000 + 15785844 22 XXXXXXX.iOS 0x102594894 0x102560000 + 215188 23 XXXXXXX.iOS 0x102902010 0x102560000 + 3809296 24 XXXXXXX.iOS 0x103c88118 0x102560000 + 24281368 25 XXXXXXX.iOS 0x103d1ebc0 0x102560000 + 24898496 26 XXXXXXX.iOS 0x103d23dc0 0x102560000 + 24919488 27 XXXXXXX.iOS 0x103c6d5c4 0x102560000 + 24171972 28 XXXXXXX.iOS 0x103dc4180 0x102560000 + 25575808 29 XXXXXXX.iOS 0x10259434c 0x102560000 + 213836 30 dyld 0x104318190 0x104300000 + 98704