Failed to create/backup SQL SSB certificate error when moving SCCM database

[PH25]

Hi,

Has anyone come across this before? I am moving our SCCM database from SQL 2012 on a 2012r2 server to SQL 2019 on a 2019 server, by recovering from a backup.  All seems to have gone fine, until the final step of running config manager setup again to choose the site maintenance option, to 'modify SQL server configuration', in order to point SCCM to the new server that is now hosting the database.
 

 ERROR: SQL Server error: [42000][137][Microsoft][SQL Server Native Client 11.0][SQL Server]Must declare the scalar variable "@String". : dbo.spCreateAndBackupSQLCert
Create_BackupSQLCert : Failed to execute spCreateAndBackupSQLCert
CSiteControlSetup::SetupCertificateForSSB : Failed to create/backup SQL SSB certificate.
ERROR: Failed to set up SQL Server certificate for service broker on "SERVER NAME" .

I have enabled broker, set trustworthy on and honor broker priority on, on the new instance before running setup.exe again.  

From some reading online, I believe it could be something to do with setting up SCCM initially with one account, but then changing it to another domain account running the service(s) and now somehow not being able to unlock the master key for the database certs.  Sorry if this is making no sense, I am no SQL expert.

Being right at the final stage of moving the database, I'm really stuck with this issue now, so any advice/pointers would be greatly welcomed, even if it's just to point me in the direction of which account I need to try to figure out was initially running things - I'm not clear whether that means the account running the config mgr console, the database instance, or the running the sql or sccm services.

Thanks
Paul

[PH25]

Update - I've decided that rather than move just the SCCM DB, I'll build a new site with a fresh DB and do a side-by-side migration. 

Although, If anyone does know the answer to the error above, I'd still be interested to know.