Matrix failed media with MSC3916 "Authentication for media"

[mahdi1234]

With recent switch on many matrix servers to authenticated media, matterbridge doesn't handle it correctly anymore even when Media server set. With v1.26.0

time="2024-09-06T13:23:47+02:00" level=debug msg="== Receiving event: &gomatrix.Event{StateKey:(*string)(nil), Sender:"@someaccount:matrix.org", Type:"m.room.message", Timestamp:1725621827645, ID:"$someid", RoomID:"!someroom:matrix.org", Redacts:"", Unsigned:map[string]interface {}{"age":301, "membership":"join"}, Content:map[string]interface {}{"body":"barcode.gif", "info":map[string]interface {}{"h":100, "mimetype":"image/gif", "size":1676, "w":100, "xyz.amorgan.blurhash":"xyz"}, "m.mentions":map[string]interface {}{}, "msgtype":"m.image", "url":"mxc://matrix.org/someurl"}, PrevContent:map[string]interface {}(nil)}" func=handleEvent file="bridge/matrix/matrix.go:484" prefix=matrix
time="2024-09-06T13:23:48+02:00" level=debug msg="Trying to download "barcode.gif" with size 1676" func=HandleDownloadSize file="bridge/helper/helper.go:162" prefix=matrix
time="2024-09-06T13:23:48+02:00" level=debug msg="Download OK "barcode.gif" 45" func=HandleDownloadData2 file="bridge/helper/helper.go:183" prefix=matrix

In the snippet above, there was image called barcode.gif with size of 1676 bytes posted, but in reality only 45 bytes downloaded.

Content of that file shows it wasn't properly authenticated.

cat ./barcode.gif 
{"errcode":"M_NOT_FOUND","error":"Not found"}

Here's some context:
matrix-org/matrix-spec-proposals#3916
https://matrix.org/blog/2024/06/26/sunsetting-unauthenticated-media/

[Vetgans]

Can confirm.

I can still receive images, but not send them anymore.