Works again, thanks!
Looks like I’m getting the same issue today 
Am I the only one ?
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by ‘ReadTimeoutError(“HTTPSConnectionPool(host=‘wheels.vtk.org’, port=443): Read timed out. (read timeout=15)”)’: /vtk-osmesa/
ERROR: Could not find a version that satisfies the requirement vtk-osmesa==9.3.* (from versions: none)
ERROR: No matching distribution found for vtk-osmesa==9.3.*
It seems to work…maybe a temporary issue on my side.