When sending an approval email through Flow, if no answer is received within 30 days, the Flow times out and fails.
In some cases, 30 days is not enough time to receive an approval.
Please increase Flow approval timeout to 60 or 90 days.
You can now do this with the new Create Approval (v2) action. Read more here: https://flow.microsoft.com/en-us/blog/2019-release-wave-2-plan-and-may-updates-for-microsoft-flow/
Flow lifetime shouldn't be limited ! Some process takes sereral months even years !
I fully agree @Mélisen
Thanks for all the support everyone. Please pass it on, get some votes, let's make this happen!