See the attached document to diagnose and try to free a stuck relay in molbox1, molbox1+ or molbox RFM flow terminal. It basically describes how to use the front panel buttons to cycle the relays. Note that with molbox1+ firmware version 6.01, the keys to press to enter diagnostic mode have changed. New method is to press and hold the left and right arrow keys at the same time.
A stuck relay might show as PRTERR, TIMEOUT, CALCERR, or ACALERR
Another possibility would be that the driver board cable has come loose. This is easy to inspect by removing the top cover of a molbox1 or molbox1+ terminal. See the attached article "check back panel internal cable, molbox1+.pdf" to check this.
If you have a problem with a single molbloc you can check it with the article at this link, Check molbloc PRT or ACAL error
Note that molbox1+ terminals shipped new since July 2017 should only get this error as a result of the back panel cable being loose, not from a relay being stuck (type of relay was changed in July 2017).
If this procedure does not work, contact Fluke Calibration Service for a RMA number to return the molbloc element or molbox terminal for evaluation/repair. By phone at +1.877.355.3225 or the below link.
If you have technical questions contact Flow Technical Support at the same phone number or at the below link.