App crash at saving uuid in KeychainItemWrapper.m in iPad Air (IOS Swift)

Question

My app crashes in iPad Air,os 12.2.0.. the crashlytics in Fabric shows the crash at line 315

NSAssert( result == noErr, @"Couldn't add the Keychain Item." );

in KeychainItemWrapper.m file. This method is called to store UUID in app :

func getUUIDString() -> String {
        if !uuid.trimmed().isEmpty {
            print("uuid ==> \(uuid)")
            return uuid // return cached value
        }
        /// Generate A Dynamic UDID
        var toRet = ""
        /// Wrapper Object
        let keychainWrapperObj = KeychainItemWrapper(identifier: "ManDown", accessGroup: nil)
        /// Check is Any UDID Stored
        if let udidSavedVal = keychainWrapperObj?.object(forKey: kSecAttrService) {
            print("Old UDID is being Used now as ==> \(udidSavedVal as? String ?? "")")
            toRet = udidSavedVal as? String ?? ""
        }

        if toRet.trimmed().isEmpty {
            /// We have no UDID Saved Need to get New
            if UserDefaultManager.getUUIDSaved() != nil {
                toRet = UserDefaultManager.getUUIDSaved()!

//The line causing crash keychainwraper.setobject()

                keychainWrapperObj?.setObject(toRet, forKey: kSecAttrService)


            } else {
                /// Need to Get new UUID
                var newUUIDStr: String?
                newUUIDStr = UIDevice.current.identifierForVendor!.uuidString
                print(newUUIDStr!)
                UserDefaultManager.saveUUIDInDefaultAs(UUIDString: newUUIDStr!)
                toRet = newUUIDStr!
                keychainWrapperObj?.setObject(toRet, forKey: kSecAttrService)
            }
        }

        print("uuid ==> \(toRet)")
        uuid = toRet
        Crashlytics.sharedInstance().setUserName(uuid)
        return uuid
    }

Well my question is how can I solve this crash and how can I at least replicate this error for further debugging. Xcode 10.2 swift 4 The capability is not on for keychainSharing, but the app is still working fine.

Error logs: 
Fatal Exception: NSInternalInconsistencyException
0  CoreFoundation                 0x191b53518 __exceptionPreprocess
1  libobjc.A.dylib                0x190d2e9f8 objc_exception_throw
2  CoreFoundation                 0x191a6d148 +[_CFXNotificationTokenRegistration keyCallbacks]
3  Foundation                     0x1925301c8 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:]