RE: Webservice link changes when syncing to Power BI and the data refresh fails because of that
This is reported in the following Yammer thread
www.yammer.com/.../
(if you do not have access, I will report this down below)
This dates back to 15th September
...
Dear Partners, just a heads-up on a known issue with the Power BI integration (failed refresh of reports). A recent bugfix in the cloud platform caused an unexpected side effect related to environment name lower/uppercase and reports created in the past using Power BI Desktop. We are working on a possible solution but to easily mitigate this a manual update is needed to re-select or re-type the environment name – either in Power BI Desktop where the report was created or directly in the Power BI website (dataset settings):

and on 16th another update
Update for partners/customers:
current plan is to quickly (meaning today, next few hours) revert back so the older, untouched reports will now start refreshing. In the meantime we will improve Power BI connector so it becomes resilient to such changes. The only downside is that the reports manually updated yesterday/right now would need to be updated again later on unless they have UPPERCASE environment name (the safest way to refer to environment from now on) – so we would suggest to hold on for now.
BTW this change has happened already so the untouched reports should be unaffected from now on...