In the Sales and marketing parameters in D365 F&SCM, set the Opportunities parameters to 'Never'.
If the integration between D365 F&SCM and STAEDEAN Rental Management for D365 Sales is active, opportunities are managed in STAEDEAN Rental Management for D365 Sales. So, it is not desirable that opportunities are created in D365 F&SCM.
If not set to 'Never', on synchronization of (project) rental quotations from STAEDEAN Rental Management for D365 Sales to D365 F&SCM, an error message is shown.
Steps
Go to Sales and marketing > Setup > Sales and marketing parameters.
On the General tab, set all Opportunities parameters to 'Never'.