The behavior you’re seeing, where Outlook connections appear to “drop” after a flow has been disabled for months, is expected behavior in Power Automate. Connections are
user‑owned OAuth tokens as mentioned by
@Pstork1, not long‑lived system assets.
Why this happens
Token expiration:
User connections rely on OAuth refresh tokens. When a flow is turned off for an extended period (weeks or months), those tokens can expire or be invalidated by tenant security policies.
Owner‑only rebinding:
The Flow designer can only bind connections owned by the current editor. It cannot re‑authenticate or recover connections created by other users who are not actively editing the flow.
Orphaned metadata state:
Disabling a flow for long periods effectively freezes its configuration. When re‑enabled later, previously valid user connections may no longer be trusted or resolvable.
Recommended Solution: Use a Service Account Model
For seasonal or long‑lived flows, avoid user‑specific email connections.
1. Use a service account or shared mailbox (best practice)
- Create a single Outlook connection using a service account or shared mailbox
- Use “Send an email from a shared mailbox (V2)”
- This connection remains stable regardless of who saves files or turns the flow on/off
2. Handle the user identity dynamically
- Capture the file creator using trigger metadata
- Include it in the email body (for example: “Submitted by: ”)
- This avoids dependency on the sender identity
3. “Send As” scenarios (not recommended)
While it is technically possible to grant Send As permissions, this is high‑maintenance and fragile at scale. A shared mailbox approach is far more reliable for production and seasonal flows.
Summary
Individual Outlook connections are intended for personal workflows
Long‑disabled flows will eventually lose user‑owned connections
A service account or shared mailbox is the correct enterprise pattern
This avoids annual reconfiguration and connection breakage
Bottom line: Your original design worked functionally, but it isn’t durable. Switching to a single, non‑user‑owned connection is the supported and stable solution.
