We have a web application where sometimes the request are broken on irregular basis and only using the Firefox browser the error that comes up is :

SSL_ERROR_BAD_MAC_READ 
-12273 
"SSL received a record with an incorrect Message Authentication Code."

One customer claimes that they have this error about every 3 minutes but the others doesn't have this problem, but the other customers have this problem only a few times.

Any idea how find out the source of that problem?

I browsed a little through the Firefox code and found that 

if (NSS_SecureMemcmp(mac, pBuf, macLen) != 0) {
    /* MAC's didn't match... */
    SSL_DBG(("%d: SSL[%d]: mac check failed, seq=%d",
         SSL_GETPID(), ss->fd, ss->sec.rcvSequence));
    PRINT_BUF(1, (ss, "computed mac:", mac, macLen));
    PRINT_BUF(1, (ss, "received mac:", pBuf, macLen));
    PORT_SetError(SSL_ERROR_BAD_MAC_READ);
    rv = SECFailure;
    goto cleanup;
}

Obviously it is possible to see what was the received mac and what was the computed mac...anyone know where those logs are in FF or maybe I should enable some logging in FF?

Where can I find the logs for this in Firefox?

firefox ssl
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