Internal error: No module named cee.plugins.views.graphs An internal error occured while processing your request. You can report this issue to the Check_MK team to help fixing this issue. Please use the form below for reporting

I will try another install in parallel with version 1.6.0p13 Raw for the master and a slave.
I saw in the forum a similar problem and @andreas-doehler advised version 1.6.0p13 or p12 because this problem does not occur

I will get back to you for the result