As often occurs when soliciting advice on the internet, you received two answers with completely opposite recommendations. To break the tie, I can tell you this:
DO NOT apply any sort of grease--even fancy expensive "dielectric grease", which is what I think you mean by "die" grease--to any electrical connector's actual contacts. Check with the manufacturer to see if they recommend using any sort of grease on the connector body seals. Most modern electrical connectors do not require application of dielectric grease, and many specifically say to not use grease. Dielectric grease is an excellent insulator and does not help any contact conduct electrical current. In some instances it can be useful as a lubricant--that is why they call it grease. The "dielectric" part means it is grease that does not conduct any electrical current.
