OME configuration failing for iDRAC8

I have eight blades (six FC630s across three FX2 chassis, two M630s in a VRTX chassis) all running the Dell ESXi 6.5 image, and I'm running into issues getting OME to create a configuration template for any of them.

I successfully created chassis templates and associated them to all of the chassis, but when I try to create a server template for any of the blades I receive:

Extracting XML from target: ($dracIP)
Protocol failed to execute commands on target $dracIP with error: Could not find a description for error #80338043

Failed to get the server config file from the target $deviceName.

I receive the same error if I try to run a Configuration Inventory, and hardware logs are not pulled either. The devices are discovered both as RAC and ESX Servers, hardware inventory (Mem/CPU/etc) is correctly populated on the Device Details tab.

I've removed the device & discovery range and bumped the WSMAN timeout up to 120s as suggested in previous posts, but that had no effect. Using the Troubleshooting utility to test WSMAN communication appears to succeed, it connects & displays 33 supported WSMAN profiles after warning about the TLS1.0 handshake failing, but the OME server runs 2012R2 & the devices are successfully discovered so that doesn't seem to be the problem.