When uploading certificates for Universal Links, you may experience an error message:
Intermediate CA certificate must be included in certificate chain.
When receiving your certificates, you may have a file included named something like providernameBundleCert.crt along with your link domain certificates.
If so, you will need to append the contents of that file to each of you .crt files.
To do this you'll open each file in a text editor:
1. Open providernameBundleCert.crt in a text editor
2. Copy the contents of this file
3. Open one of the .crt files in a text editor. For example, link.yourdomain.com.crt
4. Paste the contents of providernameBundleCert.crt at the end of the data in link.yourdomain.com.crt
5. Save link.yourdomain.com.crt in a separate folder
6. Upload the new version of link.yourdomain.com.crt and the original version of link.yourdomain.com.key.
Note that its very important that the content of providernameBundleCert.crt is at the end of each .crt file.