Since this week I am having identical problems as described in kb49303 (http://kb.paessler.com/en/topic/49303-unable-to-see-historical-data-in-report).
Reports for other (ping, snmp) sensors work, only not for bandwidth/traffic sensors. For these the graphs are empty in PDF reports (see attached example). I am able to view them under live/historical data and create HTML-based reports however, so the data does exist and is available for PRTG.
Tried and tested; - Setup > Systeem beheer > Systeembeheer > Recalculate PRTG Graph Data Cache - Restart server
Both to no avail.
Could you please help me solve this puzzle? PRTG version: 22.214.171.124.1799