I'm having the same issue w/ an apache reverse proxy.  I get the following error in the apache logs:

[Sat May 27 14:08:34.665488 2017] [http:error] [pid 8845] [client xx.xx.xx.xx:16823] AH02429: Response header name ';expires=Mon, 26-Jun-2017 14' contains invalid characters, aborting request

I found the following reference to a recent apache patch that puts a hard stop on invalid headers:

https://blog.tigertech.net/posts/apache-cve-2016-8743/

I suspect this is the issue for anyone running an up to date apache reverse proxy.  Any chance of a fix?

Edit:

Just realized there is a 2.0.2 beta available and I'm running 1.10.1.  I'm going to give the beta a go and see if that fixes the reverse proxy header issues.

Edit2:

Just installed 2.0.2 and it works great behind the proxy.  All is well again.