Use the debug log in the plugin, that may explain why.
I activate debug log, but when I log into my dashboard, was deleted even debug log file!
Here debug log read from ftp:
08:37:26 /wp-admin/options-general.php?page=wpsupercache&tab=debug gc: deleted /var/www/comerisparmio.net/wp-content/cache/meta, forced delete
08:37:53 / supercache dir: /var/www/comerisparmio.net/wp-content/cache/supercache/www.comerisparmio.net/
08:37:53 / No wp-cache file exists. Must generate a new one.
08:37:53 / In WP Cache Phase 2
08:37:53 / Setting up WordPress actions
08:37:53 / Created output buffer
08:37:53 / Output buffer callback
08:37:53 / Anonymous user detected. Only creating Supercache file.
08:37:53 / Gzipping buffer.
08:37:53 / Writing non-gzipped buffer to supercache file.
08:37:53 / Writing gzipped buffer to supercache file.
08:37:53 / Renamed temp supercache file to /var/www/comerisparmio.net/wp-content/cache/supercache/www.comerisparmio.net/index.html
08:37:53 / Renamed temp supercache gz file to /var/www/comerisparmio.net/wp-content/cache/supercache/www.comerisparmio.net/index.html.gz
08:37:53 / Writing gzip content headers. Sending buffer to browser
08:37:53 / wp_cache_shutdown_callback: collecting meta data.
08:37:53 / Did not write meta file: wp-cache-ca3e4133cbb8b604e2fe43db05883d48.meta *1* *1* *1*
08:38:15 / supercache dir: /var/www/comerisparmio.net/wp-content/cache/supercache/www.comerisparmio.net/
08:38:15 / Served page from supercache file using PHP.
08:38:53 / supercache dir: /var/www/comerisparmio.net/wp-content/cache/supercache/www.comerisparmio.net/
08:38:53 / Served page from supercache file using PHP.
08:39:11 / supercache dir: /var/www/comerisparmio.net/wp-content/cache/supercache/78.47.207.36/
08:39:11 / No wp-cache file exists. Must generate a new one.
08:39:11 / In WP Cache Phase 2
08:39:11 / Setting up WordPress actions
08:39:11 / Created output buffer
08:39:11 / Output buffer callback
08:39:11 / Buffer is blank. Output buffer may have been corrupted by another plugin or this is a redirected URL. Look for text ‘ob_start’ in the files of your plugins directory.
08:39:11 / No closing html tag. Not caching.
08:39:11 / wp_cache_shutdown_callback: collecting meta data.
08:39:11 / Did not write meta file: wp-cache-c0dcfbd1ed5b559e8befc4a02f16445b.meta ** *1* **
08:39:53 / supercache dir: /var/www/comerisparmio.net/wp-content/cache/supercache/www.comerisparmio.net/
08:39:53 / Served page from supercache file using PHP.
