File":"/***/***/***/***/***/nextcloud/3rdparty/guzzlehttp/guzzle/src/Handler/CurlFactory.php",
"Line":211,
"CustomMessage":"cURL error 60: SSL certificate problem: certificate has expired (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://apps.nextcloud.com/api/v1/categories.json"
Read this
I think only your shared hoster can delete DST_Root_CA_X3 .
( rm /etc/ssl/certs/DST_Root_CA_X3.pem )