Download from ESET repository fails

[kschmitz 0]

On one of our sites I get the following error when trying to deploy new product versions:
Software installation failed: GetFile: Cannot connect to host 'repository.eset.com' [error code: 20003, previous: 20004]
From other posts here I reckon error 20004 is the attempt to access the repository via proxy, error 20003 the following attempt by direct access to internet (which is forbidden within domain network, so no surprise there).
The thing I need to fix is the failed installation via proxy (in the agent configuration). I can access hxxp://repository.eset.com/v1/info.meta and download the metafile. The same proxy is also in the config of the security product for pattern updates and works without problem.