How do I change SMTP mail relay server?

For many years we've relay-routed our IBMi-generated emails to an internal email server on a Win10 box (MAILSVR1), and that's worked fine. Now TPTB have set us up with hosted outlook.com server. To test it, we've set up another internal mail server on a separate Win10 box (MAILSVR2). I know that I need to change the forwarding hub info.

MAILSVR1 receives email from the i and relays it to the outlook.com server
MAILSVR2 will do the same thing, once I get the forwarding hub working...

Here's what we have that works in CHGSMTPA, using MAILSVR2:

Autostart server . . . . . . . . *NO
Clear e-mail on start-up . . . . *NO
E-mail directory type . . . . . *SMTPMSF
Retries by minute:
Number of retries . . . . . . 3
Time interval . . . . . . . . 30
Retries by day:
Number of retries . . . . . . 0
Time interval . . . . . . . . 0
Retries by hour:
Number of retries . . . . . . 0
Time interval . . . . . . . . 0
Coded character set identifier 819
Journal . . . . . . . . . . . . *YES
Support ETRN for server . . . . *NO
Delivery status notification:
Responsible person . . . . . . *NONE
Subsystem description . . . . . QSYSWRK
Library . . . . . . . . . . . QSYS
Realtime Blackhole List . . . . *NONE
Allow relayed mail . . . . . . . *NONE
+ for more values
POP send mail window . . . . . . *NONE
Interface/domain association . . *NONE
Filter mail for virus . . . . . *NONE
Override reject connect list . . *YES
Allow bare line feed . . . . . . *NO
Verify identification . . . . . *YES
Allow authentication . . . . . . *NONE
Verify MSF messages . . . . . . *NO
Verify from user . . . . . . . . *NONE
Forwarding mailhub server . . . 'MAILSVR1'
Allow e-mail over implicit SSL *NO
Max incoming e-mail messages . . *DFT
Max outgoing e-mail messages . . *DFT
Keep until . . . . . . . . . . . *DFT
Maximum e-mail message size . . *DFT
SMTP domain alias . . . . . . . *NONE


However, when I change the FWDHUBSVR value to 'MAILSVR2' and restart the smtp server, the email is still routed to MAILSVR1. Both MAILSVR1 and MAILSVR2 are defined in CFGTCP option 10, Host Table Entries, and are pingable.

What else should I look at?

Thanks
TomH