Comment (by Roland Haas):

Hello,

if you are using a version of the ET from before ET_2020_05 then you most likely are seeing (a variant of) issue #380.

My recollection is that there is a workaround in older versions (ET_2020_05 should not be affected) was to ensure that (before checkpointing, I am not sure if one can change these after the simulation starts) ensure that:

ADMBase::metric_timelevels = 3

is in your parfile.

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2433/resubmit-failed-to-run