My understanding of the ^8.0.0 pattern is that npm/yarn will install the latest version with 8.x.x. Therefore in my scenario the problem suddenly occured when angular has published version 8.1. So my build automatically switched to 8.1. My solution was simple - I have just changed all angular related entries in package.json from ^8.0.0 to ~8.0.0. In my opinion this pattern represents 8.0.x - therefore the angular version was nailed down to 8.0 and not switching to the problematic 8.1 version.
I found the answer elsewhere in the forum - our users in the ActiveDirectory don't have an email adress set:
https://support.aspnetzero.com/QA/Questions/6180#answer-2ce4d101-ea8a-5387-f188-39eade0e077c
AND
https://support.aspnetzero.com/QA/Questions/3121#answer-2c69c3d0-fab5-479a-8189-01157bfbaa5d
@maliming thank you for the hint with downgrading to ng 8.0.x. It is working now for me. But this can't be the solution for the long run.
Could you please post into this thread once there is a solution for higher angular versions?
Yes it is a console app. Thank you very much for pointing me the direction. Embedding our system in a custom module is what I have done already. Your second hint is new to me and exactly what I was looking for.
kind regards, marco
Thank you @ismcagdas! Indeed I forgot to look up the log file. For a while I was working with another application which logged every statement also to the console... now everything is clear again.