This MapProxy plugin tries multiple times to retrieve data from a WMS server in case an error message is detected. Wait time grows exponentially.

Just change type: wms with type: wms_retry and set an error message to be detected within the first 100 bytes. Here is an example:

sources:
  flaky_wms:
    type: wms_retry
    retry:
        error_message: Overforbruk
    req:
      url: http://flaky_wms/?

Here is the same example with all the possible settings:

sources:
  flaky_wms:
    type: wms_retry
    retry:
        error_message: Overforbruk
        encoding: utf-8
        peek_size: 100
        max_tentatives: 10
    req:
      url: http://flaky_wms/?