JASMIN file availability very patchy

[valeriupredoi]

We notice fairly frequent ie 5-10% test failures of this kind - these are not created by issues with either client or Reductionist, it's JASMIN NGINX server not being up - I need to speak to CEDA about this.

[valeriupredoi]

RE: comms with JASMIN: April 24 2-8am was a bad time for the servers; Dave Poultier mentioned: 500 / 501- tell us every time
502 / 503 / 504: tell us if you get more than 1 in 10,000. Unexpected 401 or 403 - tell us every time (i.e. - it's a public file complaining about auth, or it's token you know is valid not working). Anything else - ignore

HTTPSConnectionPool(host='esgf.ceda.ac.uk', port=443): Max retries exceeded with url: /thredds/fileServer/esg_cmip6/CMIP6/AerChemMIP/MOHC/UKESM1-0-LL/ssp370SST-lowNTCF/r1i1p1f2/Amon/cl/gn/latest/cl_Amon_UKESM1-0-LL_ssp370SST-lowNTCF_r1i1p1f2_gn_205001-209912.nc (Caused by ConnectTimeoutError(<HTTPSConnection(host='esgf.ceda.ac.uk', port=443) at 0x7f116e2f6210>, 'Connection to esgf.ceda.ac.uk timed out. (connect timeout=None)'))

-> so 408 is most of the things we get