Hi LivlT6,
Thank you for using the Support Forum. Please take a look at the WorkCentre 7655 solutions for the error you are seeing. It sounds like you may have tried most of these option so you may need to try solution number 5 to reset the system software and network controller.
For the WorkCentre 5665 take a look at the solutions for the error and make sure that your firmware is upgraded to the level mentioned in solution 4 or a higher version.
With the WorkCentre 7545 check the solutions for the error and again you may need to do a software reset.
If these do not help please consider contacting your support centre for further assistance.