求助！joomla!3.8.3+php7.2 进后台login时报错

新配置的IIS 10+php 7.2 环境，安装joomla!3.8.3后，首次进入后台，输入用户名+密码，点击登录，出现500错误页面。
开启debug后，报出错误：      

PHP Warning:  session_set_save_handler(): Cannot change save handler when session is active in *\libraries\joomla\session\storage.php on line 106

PHP Warning:  session_set_cookie_params(): Cannot change session cookie parameters when session is active in *\libraries\src\Session\Session.php on line 807