Power Platform Community Forum Thread Details

Hi,

I’ve built a flow that takes Microsoft Forms responses and writes them into an Excel Online (Business) table stored in OneDrive. The flow worked fine for about a month, but in the last 2 weeks it has started failing with different issues.

Flow structure:

Trigger: Microsoft Forms – When a new response is submitted.
Get response details
Several Compose/processing steps (e.g. building group lists, formatting date/time, calculating duration in hours).
Final step: Excel Online (Business) → Add a row into a table (in OneDrive, file = Name.xlsx)

Problems I’m seeing:

At first:

The request has SAS authentication scheme, 'MSAuth1.0' authorization scheme or internal token scheme. Only one scheme should be used.
After reconnecting again: Bad Gateway (502) errors, even when the flow runs all the way to the Excel step.
Run times also got much slower (previously ~3 minutes, now ~15 minutes).

What I already tried:

Deleted and recreated the Excel Online (Business) connection.
Made the file private (not “Anyone with the link”), shared only with people/groups.
Repointed the Add a row step using the folder picker (not by file URL).
Flow sometimes succeeds once after changes, but fails again after edits. (once suddenly worked for 2 flows)

Environment details:

File is in OneDrive for Business.
Region: Europe (northeurope, europe-002).
Table in Excel has multiple columns (including text, dates, numbers).

My questions:

Why would this flow run successfully for a month and then suddenly start failing with these auth/502 errors?
Is this a connector bug/change on Microsoft’s side (Excel Online Business or Forms)?
How to fix the issue?

Thanks in advance for any help!