The hosts file entries to block Spotify audio ad servers.

spotihosts

# taken from here:
# https://www.reddit.com/r/Piracy/comments/4kn6rq/comprehensive_guide_to_blocking_ads_on_spotify/
0.0.0.0 adclick.g.doublecklick.net
0.0.0.0 adeventtracker.spotify.com
0.0.0.0 ads-fa.spotify.com
0.0.0.0 analytics.spotify.com
0.0.0.0 audio2.spotify.com
0.0.0.0 b.scorecardresearch.com
0.0.0.0 bounceexchange.com
0.0.0.0 bs.serving-sys.com
0.0.0.0 content.bitsontherun.com
0.0.0.0 core.insightexpressai.com
0.0.0.0 crashdump.spotify.com
0.0.0.0 d2gi7ultltnc2u.cloudfront.net
0.0.0.0 d3rt1990lpmkn.cloudfront.net
0.0.0.0 desktop.spotify.com
0.0.0.0 doubleclick.net
0.0.0.0 ds.serving-sys.com
0.0.0.0 googleadservices.com
0.0.0.0 googleads.g.doubleclick.net
0.0.0.0 gtssl2-ocsp.geotrust.com
0.0.0.0 js.moatads.com
0.0.0.0 log.spotify.com
0.0.0.0 media-match.com
0.0.0.0 omaze.com
0.0.0.0 open.spotify.com
0.0.0.0 pagead46.l.doubleclick.net
0.0.0.0 pagead2.googlesyndication.com
0.0.0.0 partner.googleadservices.com
0.0.0.0 pubads.g.doubleclick.net
0.0.0.0 redirector.gvt1.com
0.0.0.0 s0.2mdn.net
0.0.0.0 securepubads.g.doubleclick.net
0.0.0.0 spclient.wg.spotify.com
0.0.0.0 tpc.googlesyndication.com
0.0.0.0 v.jwpcdn.com
0.0.0.0 video-ad-stats.googlesyndication.com
0.0.0.0 weblb-wg.gslb.spotify.com
0.0.0.0 www.googleadservices.com
0.0.0.0 www.googletagservices.com
0.0.0.0 www.omaze.com

Could adeventtrackermonitoring.spotify.com be one? I just Installed AdGuard Home on a Raspberry Pi. It is being blocked in the AdGuard DNS filter.