When scanning, all my output- modules gives a red cross

When scanning my modules, I can not access my relays expect the new ones.
All the input modules, are accessible, but all my relays are showing a red dot with cross.
I can not read nor write to these modules, but I can make them work from the computer.
VMBRY4, VMB2BL, VMB1DM, VMB1BL, VMB1TS are not accessible
The terminators have been checked.
Connection is by USB

How can I solve that problem?

These kind of problems are usually caused by bus wiring problems (bad or faulty contacts).
Please check carefully if all bus wires are correctly installed. Haven’t the +/- and H/L been switched by accident on one or more modules? Are the screws on the connectors tightly closed? Sometimes the wires are inserted at the wrong side of the opening, after which the screw is tightened but the wire remains loose (giving contact at times, and at other times not). A wire can be broken somewhere along the way also.
The LEDs on the modules can give some indication also. Is the power supply LED lit on every module? When you press any button of a random module, on all other modules the Rx and Tx LEDs should briefly flicker (a very short flicker). Modules that have the Rx and Tx continuously flickering probably experience communication errors (almost always caused by wiring problems).

Too many or not enough terminators can also be a problem, but you mention having checked that. In a normal installation, only two terminators should be closed, ideally at the longest distance possible from each other.

Hi, Thank you for your time.
I did find the error in the system, the faulty temp sensor VMB1TS. There was some oxidation inside. I knew that all the wires were all right, last month I could access the system and change everything. And I know nothing was changed. And the most bizarre was that the system kept on running without any problems. The lights were stable, but I seem to recall seeing a few days ago the VMB1TS flashing the 2 leds without any reason. I did not take any notice.