Mitsubishi QJ71E71-100 Ethernet Card Problem

[SIEGFRED]

Hello all. My name is Robert Siegfred. My company is TDS Automation L.L.C. I have recently been upgrading A-Series PLC to Q-Series and have been very fortunate not to have any issues until this latest upgrade. I have a few problems, but I'd like to focus on the most important issue first. Basically, a long story short, I can not change out the current QJ71E71-100 module with another module. That is, the system is functioning properly at the moment, and has been for over a week now, but we found that if we need to change the module, we are unable to get a new module to "take". We have done this many times without issue and the only thing uncommon I've found this time is that the current, running module has the RJ-45 connector backwards compared to all the others we've used. When we try to replace the module, it will accept it and the PLC will run, but there are never any established port connections. Has anyone ever seen this? Thank You, Rob.