Errors for filemtime() and tempnam() for App PHP

since I have solved a problem with runing cronjobs, I am getting these error-logs as I understand from cron.php. But I think this is an installation problem, so I put it in here.

Could someone please translate these Errors to me and what I have to do to get rid of them:

Error - filemtime()
{“reqId”:“@”,“level”:3,“time”:“2020-08-31T11:25:02+02:00”,“remoteAddr”:“",“user”:"–",“app”:“PHP”,“method”:“GET”,“url”:"/cron.php",“message”:“filemtime(): stat failed for / nextcloudpath/tmp//oc_tmp_EGSilr-.crt at / nextcloudpath /lib/private/TempManager.php#196”,“userAgent”:“cronBROWSE v0.93”,“version”:“”,“id”:"*”}

Error tempname()
{“reqId”:“",“level”:3,“time”:“2020-08-31T11:25:00+02:00”,“remoteAddr”:"”,“user”:"*",“app”:“PHP”,“method”:“GET”,“url”:"/index.php/settings/ajax/checksetup",“message”:“tempnam(): file created in the system’s temporary directory at /nextcloudpath /lib/private/TempManager.php#91”,“userAgent”:“Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0”,“version”:“”,“id”:""}

Thank you!

after several tesings I found out, what went wrong.
It was a permission issue. I set the right for the tmp-directory to 0644 BUT due to the webcron (I think) I hat to set the permissions to 0755. Now it works fine.

Hope someone finds this answer usefull.