So today i had a strange revelation which has the potential for a PSA in #gischat : while our #mapcache powered #wmts for #historicalmap in Hessen has worked from the start in #qgis i have received reports from #arcmap users (v10) that they could not use the service. It was showing the notorious red exclamation mark. Not being #opensource there was no way to determine the reason it failed. Turns out it was a colon in the scale (1:25.000) in the metadata title Tag. IMHO a tale to #switch2qgis