Authentication issues can usually be resolved by correcting any relevant credentials when setting up the Remote Server. However, sometimes authentication issues can occur because of IP address requirements.

Be aware of the following if the remote server enforces an IP address whitelist.

If your site uses a custom domain, you have two dedicated IPs that may be used for outbound connections. To find your dedicated IPs, type "Firewall" in the search box at the top of every page, and then click on the matching result. Scroll to the bottom of that page to find your dedicated IP addresses. You can disable the use of your dedicated IP for specific remote server mounts. You might do that if your counterparty has already whitelisted the main Files.com IP range, for example.

If you do not have a custom domain, ensure that our main IPs on this list are whitelisted, not just some of them. There are quite a lot of IPs on that list (over 80 at last count) and you need to whitelist all IPs or else you will experience failures. If whitelisting that many IP addresses is a problem for you, the solution is to move to a custom domain. This will get you a pair of IP addresses you can whitelist.