Why a brute-force attack on RAR3-HP hash fails?
Hello and a special hello to hashcat.net's regulars.

This is what I've been trying to do and I don't know why it's not working:

$ cat my.hash
$ hashcat -a 3 -m 12500 ./my.hash ?l?u?d?
hashcat (v4.1.0) starting...

* Device #1: Not a native Intel OpenCL runtime. Expect massive speed loss.
    You can use --force to override, but do not report related errors.
* Device #2: This hardware has outdated CUDA compute capability (2.1).
    For modern OpenCL performance, upgrade to hardware that supports
    CUDA compute capability version 5.0 (Maxwell) or higher.
* Device #2: WARNING! Kernel exec timeout is not disabled.
    This may cause "CL_OUT_OF_RESOURCES" or related errors.
    To disable the timeout, see:
nvmlDeviceGetCurrPcieLinkWidth(): Not Supported

nvmlDeviceGetClockInfo(): Not Supported

nvmlDeviceGetClockInfo(): Not Supported

nvmlDeviceGetTemperatureThreshold(): Not Supported

nvmlDeviceGetTemperatureThreshold(): Not Supported

nvmlDeviceGetUtilizationRates(): Not Supported

OpenCL Platform #1: The pocl project
* Device #1: pthread-Intel(R) Core(TM) i7 CPU      870  @ 2.93GHz,

OpenCL Platform #2: NVIDIA Corporation
* Device #2: GeForce GTX 460, 241/964 MB allocatable, 7MCU

Hashfile './my.hash' on line 1 (foo..._REDACTED_:0::::foo.rar): Line-length
No hashes loaded.

Started: Sat Aug 18 16:12:33 2018
Stopped: Sat Aug 18 16:12:33 2018

Any suggestions/ideas?
The hash format can be double-checked by looking at this page https://hashcat.net/wiki/example_hashes or with hashcat itself e.g. hashcat -m 12500 --example-hashes

The hash format should not contain the file/path part. You need to provide the raw hash (without file names). Please always try to run/crack the example hash if you have problems like this. Your target hashes should be similar to the example hash.