This is from deadline's error log, dlt seems to be in the right folder:
2017/10/25 09:45:56 INF: [05892] [05896] SYSTEM: Production renderer is changed to NA. Previous messages are cleared.
2017/10/25 09:45:56 DBG: [05892] [05896] Interface8::LoadFromFile(C:/Users/jcdeblok/AppData/Local/Thinkbox/Deadline9/slave/IP-A00F3/jobsData/59f03f33cd6a9cd564e4018b/34620536_recover_0029.max)
2017/10/25 09:45:56 INF: [05892] [05896] Starting to load file: C:/Users/jcdeblok/AppData/Local/Thinkbox/Deadline9/slave/IP-A00F3/jobsData/59f03f33cd6a9cd564e4018b/34620536_recover_0029.max
2017/10/25 09:45:56 WRN: [05892] [05896] Missing dll: coronautils2018.dlt - CoronaMtl
2017/10/25 09:45:56 WRN: [05892] [05896] Missing dll: coronautils2018.dlt - CoronaColor
2017/10/25 09:45:56 WRN: [05892] [05896] Missing dll: coronautils2018.dlt - CoronaSky
2017/10/25 09:45:57 WRN: [05892] [05896] Missing dll: coronautils2018.dlt - CoronaLayeredMtl
2017/10/25 09:45:57 WRN: [05892] [05896] Missing dll: coronautils2018.dlt - CoronaSun
2017/10/25 09:45:57 WRN: [05892] [05896] Missing dll: corona2018.dlr - CoronaRenderer
2017/10/25 09:45:57 WRN: [05892] [05896] Missing dll: coronautils2018.dlt - CoronaLightMtl
2017/10/25 09:45:57 INF: [05892] [05896] SYSTEM: Production renderer is changed to Scanline Renderer. Previous messages are cleared.
Official 1.7 Corona release, up to date windows x64 server 2016 datacenter (EC2).
I did cancel the first install attempt of Corona because it was downloading the mat lib, then uninstalled the remains using add/remove programs and reinstalled it again (a few times now)
So any clues?