Licensing: Is it possible to use a MDK Essential (Flex) License for a standalone compiler in Linux?

Hey guys,

is using the standalone compiler valid usage with this license and in case it is, how do I get there?

The instruction page https://developer.arm.com/documentation/ka004977/latest does not list the MDK license.
In Windows we copy our mapping file from the µVision installation folder into the mappings folder of the standalone
compiler and set the ARMLMD_LICENSE_FILE and ARM_TOOL_VARIANT accordingly.
This approach does not work in linux, instead this failes with the following message

armclang: error: Your installation could be misconfigured or corrupted.
Check that your licensing and toolkit configuration is set up correctly, using the information available at: https://developer.arm.com/tools-and-software/software-development-tools/license-management/resources/product-and-toolkit-configuration.
Information about this error is available at: http://ds.arm.com/support/lic86
 General licensing information is available at: http://ds.arm.com/support/licensing/
 If you need further help, provide this complete error report to your supplier or license.support@arm.com.
 - ARMLMD_LICENSE_FILE: 'PORT@URL'
 - LM_LICENSE_FILE: unset
 - ARM_PRODUCT_DEF: unset
 - ARM_PRODUCT_PATH: unset
 - ARM_TOOL_VARIANT: 'mdk_cm_std_flex'
 - Product location: product not found
 - Toolchain location: .../ArmCompilerforEmbedded6.18/bin
 - Selected tool variant: mdk_cm_std_flex
Product: unknown
Component: Arm Compiler for Embedded 6.18
Tool: armclang [5e4cc700]

Appreciate any hints, thanks ;)