HMI tags will not compile: Error. How to link tags?

I have the exact same issue my connections in the HMI's tag table are all red. I had to replace the PLC to a newer CPU. did the change & PLC runs 100%. The HMI tags will not compile: Error;

"The PLC referenced by the PLC tag cannot be reached thru the configured connection. "

HMI Tags > Connections - the connection seems correct,

I tried synchronizing the tags (with all the options below it, result states: Syncronization with PLC tags completed, but the connection stays red. 

The answer above of linking the tags points to an incorrect post.

How do I link the tags?

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Split from A connection configured for the tag is not available.

Hi Chrismis,

Go to HMI tags and check if the connection is marked red there. Then select all those tags and synchronize them with the PLC tags (button on the right of the export and import buttons).