Form does not get filled after upgrading to AEM6.4

We have an AEM Forms 6.2 (Turnkey), which works fine, we need to upgrade it to 6.4.

After the upgrade (we tried both in-place and fresh install), the form could not be filled, we got the following errors,

12.11.2019 14:41:37.402 *ERROR* [ [1573598470246] GET /lc/content/xfaforms/profiles/default.html HTTP/1.1] com.adobe.cq.sightly.WCMUsePojo Failed to activate Use class

java.lang.NullPointerException: null

12.11.2019 14:41:37.543 *ERROR* [ [1573598470246] GET /lc/content/xfaforms/profiles/default.html HTTP/1.1] com.adobe.cq.sightly.WCMUsePojo Failed to activate Use class

java.lang.NullPointerException: null

12.11.2019 14:41:37.544 *ERROR* [ [1573598470246] GET /lc/content/xfaforms/profiles/default.html HTTP/1.1] com.adobe.aemds.guide.addon.service.impl.fdm.DefaultFDMPrefillServiceImpl No form data model associated with adaptive form

12.11.2019 14:41:37.544 *ERROR* [ [1573598470246] GET /lc/content/xfaforms/profiles/default.html HTTP/1.1] com.adobe.fd.ccm.ccr.fdinternal.impl.services.CCRPreviewPrefillService getPrefillData  http://localhost:8080/rest/services/SABC_StudentLoan/Services/Application/Fill/New:2019.2020?ownerGUID=E0C40C3057AB4B6ABB9050DFF8BD2E06&programYear=20192020&institutionID=AJBH&partnerPortalIntegrated=1

Could somebody please advise?

Thanks,