Online Monitoring V12

[trespaser5]

Hi, I've just starting using STEP 7 V12 for the first time. The original code was written in STEP 7 V5.4 but Siemens have kindly migrated it for me. I have the authentication password from the machine builder and have uploaded all the function blocks from the PLC for good measure. The problem is the monitor button is completely greyed even though the block status says that the online/offline version is the same and I am definately online. Can anyone think of any reason why this could be ? Thanks in advance