[BUG]

[nutgram]

[BUG]

[Lukasss93]

pattern must be the exact text, try to add .* before and after your text

// before
'chat not found'

// after
'.*chat not found.*'

how to stop code execution/throw exception to catch in your code:

// custom exception
class ChatNotFoundException extends Exception{}

// routes
$bot->onApiError('.*chat not found.*', fn (Nutgram $bot, $e) {
    throw new ChatNotFoundException($e->getMessage());
});

// your code
try{
    $bot->sendMessage('Hello!', ['chat_id' => 123456789]);
} catch(ChatNotFoundException $e){
    $bot->sendMessage('chat not found!');
}