If the airSlate Lightning component cannot connect and is highlighted in a grey color with the following text: [domain name] refused to connect, follow the steps below to resolve the issue.
1. On the Salesforce main page, go to Setup and search for Security. Then, in the Security section, select Session Settings.
2. Scroll down to the Clickjack Protection section. Then, uncheck the Enable clickjack protection for customer Visualforce pages with headers disabled checkbox.
Once finished, save your settings.
If you want to leave the Enable clickjack protection for customer Visualforce pages with headers disabled checkbox ticked for security reasons, follow these steps:
On the Salesforce main page, go to Setup and search for Security. Then, in the Security section, select Session Settings.
Scroll down to the Trusted Domains for Inline Frames section. Then, click Add Domain.
For the IFrame Type select Visualforce Pages. For the Domain, enter your Salesforce lightning domain in the following format: https://your_salesforce_domain.lightningforce.com