Online Video Compressor Status

About a year ago, I developed a PS2PDF online video compressor https://www.ps2pdf.com/compress-mp4. People love our video compressor. I get like 3 - 4 thank you emails everyday. It was doing really good until May 4th. Then this happened https://imgur.com/a/toJU9kM. That drop harts. Not sure what leads to this drop. If any SEO guru can explain this, I appreciate that a lot.