TYPO3 Core

Hello,
I just set up a new typo3 installation and updated to 8.7.1 LTS.

System is working so far, but
I'm not able to load the extension manager.
When trying to load the lest an orange error list shows up in the right error (internal server error) ... xml .............

The protocol shows the error:

Core: Exception handler (WEB): Uncaught TYPO3 Exception: #1476107295: PHP Warning: curl_exec(): Unable to create temporary file, Check permissions in temporary files directory. in /is/htdocs/xxxxxxxxxxxxxxx/typo3_src-8.7.1/vendor/guzzlehttp/guzzle/src/Handler/CurlHandler.php line 40 | TYPO3\CMS\Core\Error\Exception thrown in file /is/htdocs/xxxxxxxxxxxxxxxxxxxx/typo3_src-8.7.1/typo3/sysext/core/Classes/Error/ErrorHandler.php in line 112. Requested URL: http://xxxxxxxxxxxx/typo3/index.php?M=tools_ExtensionmanagerExtensionmanager&moduleToken=219782430c1b57f3e0aff24c50e5dece6f5561c3&tx_extensionmanager_tools_extensionmanagerextensionmanager%5Baction%5D=updateExtensionListFromTer&tx_extensionmanager_tools_extensionmanagerextensionmanager%5Bcontroller%5D=UpdateFromTer&tx_extensionmanager_tools_extensionmanagerextensionmanager%5Bformat%5D=json&tx_extensionmanager_tools_extensionmanagerextensionmanager%5BforceUpdateCheck%5D=1&_=1493920690174

Regards
Bernd