php class variable not staying set

My class connects to an external site and stores the result in the $connectArray variable. A timeout value is returned so I added the CheckTime function to check that. But $connectArray is empty on reload of the class. Would someone please explain why that variable is not staying set?

    class myclass {
       public $connectArray;
       public $sessionTime;
       
       public function __construct() {
          $this->GetAccessToken();  
       }
     
       public function CheckTime() {
           if (! empty($this->connectArray->accessToken)) {
               echo 'cmp '.$this->sessionTime . ' - ' . time() + $this->connectArray->expiresIn. '<br>';
               return true;
           }

           echo 'missing details<br>';
           return false;     
       }
       
       public function GetAccessToken() {
        
           $this->CheckTime();
        
           $url = "https://example.com";
           $headers = ['userName' => "xxxx",
                       'password' => "xxxx"               
                      ];  

           $ch = curl_init();
           curl_setopt ($ch, CURLOPT_URL, $url);
           curl_setopt ($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
           curl_setopt ($ch, CURLOPT_POSTFIELDS, json_encode($headers));
           curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));        
           curl_setopt ($ch, CURLOPT_SSLVERSION, 6);
           curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, 2);  
           curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, true);                                
           curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
           curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, 5);      
           $result = curl_exec($ch);
           if (curl_error($ch)) {
               echo 'Curl error: ' . curl_error($ch);
               flush();
               ob_flush();                      
           }
           curl_close($ch);
           $this->connectArray = json_decode($result);
           
           if (! empty($this->connectArray->errorCode)) {
               $this->sessionTime = '';
               return false;
           } elseif (! empty($this->connectArray->accessToken)) {
               $this->sessionTime = time() + $this->connectArray->expiresIn;
               return true;
           }
           return false;        
       }    

    }