'Tensorboard.util' has no attribute 'Retrier'

Here is a popular issue when you want to use tensorbard with your upgraded tensorflow and tensorboard. In general you will get this issue, when you have mismatch of your tensorflow and tensorboard versions, for example you upgrade tensorflow to 1.13, but not tensorboard, you will get an error like this "Module 'tensorboard.util' has no attribute 'Retrier'". To solve this issue just do the following steps, which helped me.

1. pip uninstall tensorflow
2. pip uninstall tensorboard 
3. Make sure they are removed completely from all sources
4. clean the caches (pip or conda)
5. Reinstall tensorflow and tensorboard again (the version you prefer)

Here is some discussions

github: https://github.com/tensorflow/tensorboard/issues/1724

aipool: https://ai-pool.com/d/module__tensorboard_util__has_no_attribute__retrier_