AppleScript Crashed Question

I ran an applescript script in a Mac application,but the software crashes when it runs. This is the information I got, but I can’t get more useful information from it. Please help me, thank you.

Crashed: com.apple.root.default-qos
0 AppleScript 0x1057cae80 UASStartTellScope1(TUASCommand*) + 90
1 AppleScript 0x1057bb7d8 ReductionProc + 610
2 AppleScript 0x1057cb91d TASParser::Parse(TTerminology*, TUASValue*, char const*, unsigned long) + 1309
3 AppleScript 0x1057b330f ASCompile(AEDesc const*, int, unsigned int*) + 533
4 AppleScript 0x1057ae099 AppleScriptComponent + 1741
5 AppleScript 0x1057c8673 AGenericCall::Delegate(ComponentInstanceRecord*) + 37
6 AppleScript 0x1057c862b AGenericManager::HandleOSACall(ComponentParameters*) + 55
7 AppleScript 0x1057c7c30 GenericComponent + 108
8 OpenScripting 0x7fff915a5a4b OSACompile + 57
9 Foundation 0x7fff938715f1 -[NSAppleScript compileAndReturnError:] + 139
10 Foundation 0x7fff938718cb -[NSAppleScript(NSPrivate) _executeWithMode:andReturnError:] + 68

this is my code:

var returnString = ""
let myAppleScript = .....
var error: NSDictionary?
if let scriptObject = NSAppleScript(source: myAppleScript) {
if let outputString=scriptObject.

executeAndReturnError

(&error).stringValue {returnString = outputString} else if (error != nil) {returnString = "\(error!)"}}