Reference > Setting preferences > Setting permitted hosts preferences
 
Setting permitted hosts preferences
When you attempt to connect to a host that doesn’t support encrypted connections or whose SSL certificate cannot be verified, FileMaker Pro may notify you before it connects. Examples of actions that may display this message are opening a file hosted by FileMaker Pro or FileMaker Server, sending email to an SMTP server using a secure connection, or performing certain script steps.
If you see this message, do one of the following:
To always connect to the host, select Always permit connection to this host, then click Connect. FileMaker Pro connects to the host and adds the host to your permitted hosts list (in the Preferences dialog box). You will not receive another notification for this host for the same error.
To connect without adding the host to the permitted hosts list, click Connect.
If you are uncertain whether to permit the connection to the host, click Cancel and contact the solution developer.
To remove permitted hosts:
1. Do one of the following:
Windows: Choose Edit menu > Preferences.
macOS: Choose FileMaker Pro menu > Preferences.
2. In the Permitted Hosts tab, select one or more hosts, then press Backspace.
Notes 
FileMaker Pro automatically permits connections to hosts with verified SSL certificates and does not add them to the permitted hosts list.
For each operating system account on a computer, the user controls which hosts are added to that user’s permitted hosts list. The user’s list applies to all FileMaker Pro solutions the user opens.
Related topics 
Opening shared files as a client