Question about Vention VGA to HDMI Converter Cable

I ordered this adapter to connect a laptop (VGA) to a TV (HDMI). Test PC to TV: VGA to VGA and VGA to HDMI with adapter works perfectly, i.e. PC output and adapter cable are OK. Laptop to TV: VGA to VGA works without problems - VGA to HDMI via adapter does NOT work! VGA output seems OK, but why do I have no picture - did I miss a setting in the laptop?