dbxcli: can’t put to a folder

Here is the directory structure

humility@TNT ~/client/project: dbxcli ls
/Photos
/Public /Apps /humility /Getting Started.pdf

There is no TODO.txt in there…

humility@TNT ~/client/project: dbxcli ls /humility
/humility/_results
/humility/_dataRawUnprocessed /humility/_dataProcessed /humility/_rScripts /humility/plots

/humility/TODO

#Putting does not work

humility@TNT ~/client/project: dbxcli put TODO.txt /humility
Uploading 354 B/354 B
Error: path/conflict/folder/...

#Why?

humility@TNT ~/client/project: dbxcli put -v TODO.txt /humility
2018/05/16 09:57:49 sdk.go:93: arg: &{/humility 0xc4200da840 false 2018-05-16 13:57:49 +0000 UTC false []}
2018/05/16 09:57:49 sdk.go:93: req: &{POST https://content.dropboxapi.com/2/files/upload HTTP/1.1 1 1 map[Content-Type:[application/octet-stream] Dropbox-Api-Arg:[{"path":"/humility","mode":{".tag":"overwrite"},"autorename":false,"client_modified":"2018-05-16T13:57:49Z","mute":false}]] {0xc42000e410} <nil> 0 [] false content.dropboxapi.com map[] map[] <nil> map[]   <nil> <nil> <nil> <nil>}
Uploading 354 B/354 B
2018/05/16 09:57:49 sdk.go:93: resp: &{409 path/conflict/folder/... 409 HTTP/1.1 1 1 map[Server:[nginx] Date:[Wed, 16 May 2018 13:57:49 GMT] X-Dropbox-Request-Id:[4e305094853e28f12d39958f6f674514] Content-Type:[application/json] Connection:[keep-alive] Content-Security-Policy:[sandbox allow-forms allow-scripts] X-Robots-Tag:[noindex, nofollow, noimageindex]] 0xc4204d8080 -1 [chunked] false false map[] 0xc4200fc300 0xc42009e2c0}
2018/05/16 09:57:49 sdk.go:93: body: [123 34 101 114 114 111 114 95 115 117 109 109 97 114 121 34 58 32 34 112 97 116 104 47 99 111 110 102 108 105 99 116 47 102 111 108 100 101 114 47 46 46 46 34 44 32 34 101 114 114 111 114 34 58 32 123 34 46 116 97 103 34 58 32 34 112 97 116 104 34 44 32 34 114 101 97 115 111 110 34 58 32 123 34 46 116 97 103 34 58 32 34 99 111 110 102 108 105 99 116 34 44 32 34 99 111 110 102 108 105 99 116 34 58 32 123 34 46 116 97 103 34 58 32 34 102 111 108 100 101 114 34 125 125 44 32 34 117 112 108 111 97 100 95 115 101 115 115 105 111 110 95 105 100 34 58 32 34 65 65 65 65 65 65 65 65 65 98 102 97 99 55 79 100 110 112 120 73 54 103 34 125 125]
Error: path/conflict/folder/...

This error makes no sense to me.

If I can use a modified curl command that would be fine.