Unsupported Email Providers

Nylas is unable to connect to mailboxes hosted by the following providers:

Proton Mail

Proton Mail encrypts all messages, so Nylas is unable to read them. This is intentional by Proton Mail.

Siteground

Siteground's security policies block Nylas IPs. This is intentional by Siteground. They have indicated they will not change this. Because Nylas has a pool of IPs, you might be able to connect a grant, but it may have issues or API timeouts.

Office365 Private or National Clouds including 21Vianet

Nylas currently does not support any Office365 environment beyond the standard one. Support for other Office365 clouds is something we are considering as a future feature, but have no ETA for that.

Updated May 26, 2026 14:17