In order to resolve SSL certificate verification errors follow the instructions in the Configuring Security for FileMaker 17 and 18 support article from FileMaker. We recommend not using a Let's Encrypt certificate because they are only valid for 90 days.

LCFM Native includes an option to not verify the SSL certificate when connecting to FileMaker Server. Using this option exposes the connection to man-in-the-middle attacks, however, there are there are times where it is a useful option. For example, if your project does not sync but extracts data from the solution which is installed on a server on the local network. The LCFM Native tool includes two places to set this property.

The first is on the Syncing Checklist at step 5. Set the `Verify FileMaker Server SSL Certificate` switch to `No`.

The second is on the deployment profile editor. Uncheck the `Verify FileMaker Server SSL Certificate` checkbox.