Make sure that both HDMI>VGA Adapters are "Active" type.
"Active" HDMI>VGA adapters converts the HDMI signal from the GPU card to VGA signal BEFORE reaching the VGA Monitor. Thus it has the best compatibility than if using 'Passive".
If both are Active HMDI>VGA adapter, check your cables and see if both work on one Monitor.
Check Windows Settings - Display and see if both Monitors are showing and what Resolutions.
Are both Monitors operating on the same Resolutions?