Please make sure that SAGE is installed on the PC that you are try to connect to SAGE.
If it is, the issue is occurring due to the integration options of the export being set to the original SAGE version, before the upgrade. Please complete the following steps:-
Select options
System maintenance
System settings
General system settings
Accounting package details
Change SAGE version no to the relevant option. e.g. 25(2019) to 26(2020)
Click OK
