L-PHASE Multiband Compressor Activation problem after clean installation of Windows10

Hi all, 
I purchased Sonar platinum from Steam. Recently I am using Cakewalk from Bandlab  and it is detecting all my previously purchased cakewalk plugins from the steam version. 
But only the  L-phase Multi-band Compressor is running in demo mode, showing an error in activation.
An option to activate offline is available but it is not working. But  I can see my registered serial number and date of purchase of LP MB in cakewalk server under my account. 
Hence I am seriously stuck  amidst a very important mastering project now and really no idea what to do now. 
Kindly help me out and oblige. 
Kindest regards