SyntaxError: Unexpected token 'E', "ERROR [War"... is not valid JSON

Questions
1

Silverstripe Version: 3.7.0

Question:

I am trying to upload some images to my site and get the following error but only sometimes and there doesn’t seem to be a pattern to when it does and doesn’t work for me;

SyntaxError: Unexpected token ‘E’, “ERROR [War”… is not valid JSON

I’ve tried saving the images in different formats and as different sizes but no luck. The frustrating thing is that I have 3 sites (all using the same version of Silverstripe) and the same image will upload but one but not another.

Any help would be much appreciated!

Thanks

2

The start of that “War…” suggest that something is throwing a warning in the back end. If you examine the request/response in your browser console, you may be able to see the full message… and that should give you some hints what the actual cause is.

3

Given the casuality, I would guess this is an encoding issue, i.e. when the filename is just plain ASCII it works fine, when it cannot be (e.g. the filename has accents or other non-ASCII symbols) it fails.

I’ve seen this very same issue many times and with different causes. JSON expects all the strings in UTF-8 encoding but maybe the filesystems on the failing servers are set to Latin1.