Ncpi, odroidH1, upload no more possible after upgrade

Recently I made an update from version 18 to 19.0.2.
Since then I have problems uploading something.
When synchronizing with the desktop client the error message is

" /xyz.jpg could not be synchronized due to an error. See the log for details. "

When uploading a large file to Nextcloud, the message is

“Expected filesize of 2920660 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 8192 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.”

Does anyone have any advice?

Run ncp-report to view details from various logs, as suggested by error message.
If still relevant, use pastebin com or similar for output and post link here.