This is largely a guess, and I'll refine it as you answer some of the questions I asked.
There's an attack on TLS called logjam, where an ephemeral DH key that is way too weak is used to transport the symmetric key. IE is not vulnerable and will close the connection if the DH key is export grade (less than 1,024 bits) when the symmetric cipher is strong.
Some applications cause this situation by providing only a 512-bit ephemeral DH key even if a non-export symmetric cipher is used. This provides very little security, and IE rightly rejects it. Likely other browsers soon will too.
You need to look at how your application's TLS layer generates ephemeral DH keys. If it only has 512-bit parameters, you should immediately add support for 1024-bit parameters and use the 512-bit parameters only with export ciphers (or remove them if you don't support export ciphers).
If you're using OpenSSL, look at your calls to functions that control the selection of the ephemeral DH key. It may be sufficient to upgrade OpenSSL to a current version not vulnerable to logjam and modify your application not to call any of these functions. However, you should probably have a competent security expert review your mechanism for selecting the ephemeral DH key and make sure it's not vulnerable to logjam or broken completely (say by always using a 512-bit key).
SSL_CTX_set_tmp_dh_callback
)?