mamba: mamba install failure with current (fresh) anaconda install

1. Installing on Debian 10 in a Linux container on a Chromebook, but this has failed on Ubuntu 18 also.
2. install Anaconda using: Anaconda3-2022.05-Linux-x86_64.sh
3. then conda update -y --all
4. then check that conda-forge is the current channel (and there are no others)
5. then conda install -c conda-forge mamba
6. wait interminably as conda fails to resolve dependencies, eventually saying

(base) chet@penguin:~$ conda install -c conda-forge mamba
Collecting package metadata (current_repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.
Solving environment: failed with repodata from current_repodata.json, will retry with next repodata source.
Collecting package metadata (repodata.json): / 
done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.
Solving environment: / 
Found conflicts! Looking for incompatible packages.
This can take several minutes.  Press CTRL-C to abort.
Examining bcrypt:  25%|██████████████████████████████████████████████▎                                                                                                                                         | 110/437 [07:07<1:04:57, 11.92s/- (base) chet@penguin:~$ 

Eventually it failed, but without an error-message.