Multiple Monitors Inspiron 5567

I have a problem connecting multiple monitors on my Inspiron 5567.

I have both the Intel HD graphics 620 and the AMD Radeon R7 M440.

At 1 work location I can use my laptop display and 2 external monitors with no problem. At another work location I can only use my laptop display and either 1 of 2 (bot not both at the same time) external monitors.

Work 1: Monitor 1: I use an HDMI to DVI adapter and Monitor 1 works great. Monitor 2: I use a VicTsing USB to VGA Converter (with its own video card, which uses the latest Fresco Logic driver) and it works great.

Work 2: Here's the problem. Both monitors have VGA only, so I use a Rankie Active HDMI to VGA Adapter Converter for Monitor 1 and that works great. I connect the same VicTsing USB to VGA Converter as above and Monitor 2 displays, but Monitor 1 cuts out and the power light on Monitor 1 just flashes - the monitor seems to detect that something is connected, but can't display anything. As soon as I disconnect the USB to VGA Converter, Monitor 1 works again.

What is going on here?