topic Re: Add attachment, status code 500 in ArcGIS Connectors for Power Automate Questions

Add attachment, status code 500

abureaux — Fri, 31 Oct 2025 15:41:26 GMT

Using the Add Attachment action in Power Automate, I am getting Status Code 500, which indicates a server issue.

"body": { "success": false, "message": "AxiosError: Request failed with status code 500. " }

This flow was working fine until last night, and nothing has changed on my server. I am also able to manually upload this file to the appropriate record myself:

I'm not sure what the issue would be on my end. Is this an Esri issue?

EDIT: It's worth noting that there are no errors in Server Manager, and everything else (e.g., flows and server tasks) is working properly.

Re: Add attachment, status code 500

AkshayHarshe — Fri, 31 Oct 2025 17:27:15 GMT

@abureaux That is interesting. Can you please share what steps are you running and what connector you are using?

Re: Add attachment, status code 500

abureaux — Fri, 31 Oct 2025 18:48:14 GMT

As mentioned, the 'Add attachment' step, but specifically for the Enterprise connector:

It's in a Do until to try until Success equals true

This is the extent of the explanation I get (raw json above), so not much to go off:

Re: Add attachment, status code 500

abureaux — Fri, 31 Oct 2025 18:54:50 GMT

I will also add that this flow watches an inbox for lab results. Because this project only allows 1 set of lab results per year, I filter the record for attachments, and then delete all attachments from the current year. This is working properly. So it is finding the correct record in the correct layer and modifying it.

Here it is successfully deleting the attachment I manually uploaded, just moments before failing to upload that same attachment itself:

Re: Add attachment, status code 500

abureaux — Tue, 04 Nov 2025 15:42:17 GMT

@AkshayHarshe any ideas? I have opened a case today for this as the issue is ongoing and quite an issue.

Case number: 04039745

Re: Add attachment, status code 500

AkshayHarshe — Tue, 04 Nov 2025 21:31:50 GMT

I don't have many ideas since you are saying that it was working previously. Has something changed on your Enterprise Security wise? Seems like Power Automate doesn't have access to your Enterprise or the feature layer. See if all the necessary ports for webhooks are open if you are using them:

ArcGIS Enterprise ports

Also, In the Raw outputs of the `Add Attachments` action what version do you see under

"arcgis_connector_version": "Enterprise 2025.2.0 2025.06.10 1749573699153 361de8",

Re: Add attachment, status code 500

abureaux — Tue, 04 Nov 2025 21:53:29 GMT

We upgraded from 11.3 > 11.5 over a month ago. That is the only real change. There is a chance this particular flow, which is the only one using Add Attachment, hasn't run since 11.3. I forwarded the port diagram off to my IT for them to check.

Beyond that, server should be unchanged.

Same connector version as yours:

{ "statusCode": 400, "headers": { "ETag": "W/\"xyz\"", "arcgis_connector_version": "Enterprise 2025.2.0 2025.06.10 1749573699153 361de8", "X-Powered-By": "Express", "x-ms-environment-id": "default-xyz", "x-ms-tenant-id": "xyz", "x-ms-dlp-re": "-|-", "x-ms-dlp-gu": "-|-", "x-ms-dlp-ef": "-|-/-|-|-", "x-ms-mip-sl": "-|-|-|-", "Timing-Allow-Origin": "*", "x-ms-apihub-cached-response": "true", "x-ms-apihub-obo": "false", "Date": "Tue, 04 Nov 2025 21:41:23 GMT", "Content-Length": "91", "Content-Type": "application/json" }, "body": { "success": false, "message": "AxiosError: Request failed with status code 500. " } }

Re: Add attachment, status code 500

AkshayHarshe — Wed, 05 Nov 2025 21:41:25 GMT

@abureaux That is weird, Can you share a screenshot of your Add attachment inputs. I am curious because, your delete attachment is working.

It could still be uploading/ creating a file that is somehow blocked.

Re: Add attachment, status code 500

abureaux — Thu, 06 Nov 2025 15:41:14 GMT

From the simplified test I set-up. All I am doing is getting a file, and then trying to upload it.

Again, I can manually upload a file to this same FL. And in this same flow, I can even Query Attachment and Delete Attachment successfully:

It really is just "Add Attachment" that isn't working:

Re: Add attachment, status code 500

AkshayHarshe — Thu, 06 Nov 2025 21:52:32 GMT

I think attachment name needs an extension .pdf. See if that works.

Re: Add attachment, status code 500

abureaux — Thu, 06 Nov 2025 22:20:32 GMT

omg... Well, I just deleted my last post. This is working again!

The problem? utcNow() and/or special characters...

I changed the file name from "Test-utcNow().pdf" to "Test.pdf" and it is working again. I only thought to test this when I compared my simple flow with my main flow and realized the file name structure was the same.

I will follow up with the Esri rep as this sounds like a bug on your end.

Re: Add attachment, status code 500

abureaux — Thu, 06 Nov 2025 22:41:47 GMT

I'll poke at this more tomorrow. But in my quick testing:

Works	Doesn't work
Test.pdf	Test<utcNow()>.pdf
Test 2.pdf	Test2025-11-06T22:33:20.0657585Z.pdf*
Test-2.pdf	Test2025-11-06T22:33:200657585Z.pdf
Test~!@#$%^&*()_+=-{}][:"';?><,./2.pdf	5:5.pdf
Test2025-11-06T2233200657585Z.pdf
Test2025-11-06T223320.0657585Z.pdf
A:5.pdf

* Note that this is the outcome of "Test<utcNow()>.pdf", just as plain text.

After test #1 of the Doesn't work side failed, I wanted to test if it was the expression causing the issue, or a character in the utcNow() output that was. I narrowed it down to the : character. Problem is, I already tested the : character when I put in a bunch of random special characters into the string (test #4 of the Works column).

@AkshayHarshe please see the final two tests in each column. This is SUPER specific issue where the : symbol causes the issue only when surrounded by numbers (e.g., in a time stamp)

Re: Add attachment, status code 500

AkshayHarshe — Fri, 07 Nov 2025 14:35:11 GMT

@abureaux Thanks for giving it a thorough test run. I will try to reproduce this issue at my end and see if this is related to the connector or the Add attachment api. I feel this might be an issue with the API since we just send all the request to the API directly. Did you say this was working with the same file name through MapViewer or the Add attachment endpoint?

Re: Add attachment, status code 500

abureaux — Fri, 07 Nov 2025 16:04:40 GMT

Add attachment.

The one thing I wasn't able to test (which may be related to the error) manually uploading a file with a date/time tag as windows doesn't accept the : character in file names. As such, I can't try manually uploading a file named , for example, "Test2025-11-06T22:33:20.0657585Z.pdf".

Re: Add attachment, status code 500

abureaux — Tue, 18 Nov 2025 20:29:07 GMT

Okay, this is officially closed.

The fix: Modify the timestamp within the file name to remove all colons ":". You can do this within Power Automate via the formatDateTime() expression. E.g., formatDateTime(utcNow(),'yyyy-MMM-dd HH-mm-ss')

As I mentioned, this changed overnight and is an undocumented requirement. Before this issue appeared, timestamps were allowed in file names (e.g., #:#). As of now, in my testing A:# and #:A both work, but #:# does not work.

Esri is unsure if this is intended behaviour or not. I requested that they update the documentation for this connector. IMO, best practice is to name your files as per Windows' Naming Files, Paths, and Namespaces.