FileMaker does not accept reverse proxy SSL certificate

Question

Hi people, 
 I hope this is the correct forum. It took me some time before I found out how to even post a question. 
 I have this FileMaker database server which is sitting in the private network. Using NAT, I have configured all traffic over port 5003 to go to the internal IP of that server. 
 Because it is using SSL encryption, I have set up a reverse proxy entry for https, and linked my domain it's wild card certificate to it, and I am passing host headers. 
 That worked fine until some months ago, don't know exactly, probably after some upgrade or update. 
 Now, when I connect from the outside to the server, it is telling me that the certificate is invalid. There is a button to look at the certificate from that dialog, and it shows that all parts of the certificate ( cert, intermediate, CA ) are all OK. 
 This does not happen when I connect from the inside, using the same DNS name. 
 I realise this is not exactly main stream http / https proxying, but just maybe someone has experience here with this particular setup.

clarifix · Accepted Answer

I found the solution to the problem.

Using www.markbrilman.nl/.../ as documentation I created a pfx file that contains the main AND the intermediate certificate. I first removed the old wildcard crt file from the firewall, then imported the pfx file, and assigned it to the virtual servers that run over https.

They now return a green A sign on sslabs and... the FileMaker client problem disappeared!!

Thanks for helping me understand and fix this problem.