Error with WinSCP when security token is too large when connecting to S3 :: Support Forum

deneman Guest

Error with WinSCP when security token is too large when connecting to S3

2025-09-25 09:09

When using WinSCP to access the service, if the security token is too large, I get the following error message:

The security token included in this request is invalid.

However, performing the exact same operation with mc (MinIO Client) works correctly.

winscp.png (12.88 KB)

Description: screenshot of error message displayed by winscp

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martin◆ Site Admin
Joined:: 2002-12-10
Posts:: 42,398
Location:: Prague, Czechia

Re: Error with WinSCP when security token is too large when connecting to S3

2025-09-29

Thanks for your report. How large is too large?

Please attach a full session log file showing the problem (using the latest version of WinSCP).

To generate the session log file, enable logging, log in to your server and do the operation and only the operation that causes the error. Submit the log with your post as an attachment. Note that passwords and passphrases not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem). If you do not want to post the log publicly, you can mark the attachment as private.

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DonatienEneman Guest

2025-09-29 09:17

Here is the filelog.

When i compared with one working example i see that some informations are missing in the log for example x-amz-security-token. However, I've check "save password and sensitive" info! I think this can explain why it's not working :)