Add Phone - MAC String Property Error

[mbear2k]

Trying to add a second Cisco 7945 phone. First one provisioned with no issue and works well with some tweaking.

Adding my second phone, I am getting the error below. I've triple checked the MAC and this is correct - E0889D945DEB.

Any thoughts? MAC is not editable on these phones.

 

[craigreilly]

Is there an extra space before (maybe after) the Mac address (in the red box)? Kind of looks like it ... as that is a valid address.
I tested the MAC on my 3cx System and it worked fine.

 

[JohnS_3CX]

Indeed it would appear so as @craigreilly pointed out. I can confirm mine accepts it too without the space.