Boundary refused characters

Hi

 

When I execute a post with an attachment, Load UI generates a boundary (I already removed the quotes) like this

Content-Type: multipart/form-data; boundary="----=_Part_63_784287734.1559741312548"

 

And the "Attachment part"

------=_Part_63_784287734.1559741312548
Content-Type: application/pdf
Content-Disposition: form-data; name="file"; filename="DPA Piece 1.pdf"

 

The access management of our application refuse (I think) some characters within the name of the boundary section:

I find in the logs

HTTP 403

[msg "Failed to parse request body."] [data "Multipart: Invalid boundary in C-T (characters)."] [severity "CRITICAL"] [ver "OWASP_CRS/3.0.0"]

 

When I execute from a web brower with a name = ------WebKitFormBoundaryCz9zYIwaDfkUV9bO, I don't have the issue.

 

Any idea how to change he name of the boundary?

 

Thanks