When syncing email messages with a provider, Nylas requires a persistent unique identifier across sessions to ensure data remains consistent and up-to-date. When Nylas syncs an IMAP account, it uses two important identifiers to link the locally cached email messages with those that exist on the IMAP server:
If any UID
s changed between sessions, the provider uses the UIDVALIDITY
value to signal that you need to clear your cache and look for the new UID
s assigned to email messages.
Error: Stopped due to too many UIDVALIDITY resyncs
Resynced more than MAX_UIDINVALID_RESYNCS in a row. Stopping sync.
If an account is in a Stopped state and the mailsync logs return the error above, this indicates that Nylas stopped syncing the account due to inconsistent UIDVALIDITY
values between sessions. Because Nylas syncs across multiple sessions for an account, if UIDVALIDITY
changes constantly, Nylas cannot link IMAP UID
s and cannot maintain consistent user data.
UIDVALIDITY and empty folders
In some cases, the UIDVALIDITY
error is triggered on folders which contain no email messages (and so have no UIDVALIDITY
values). If this happens, the end user can either delete their empty folders as a workaround, or they can put at least one email message in every empty folder to generate its UIDVALIDITY
value and allow their account to resync.
UIDVALIDITY and Amazon WorkMail
Resynced more than MAX_UIDINVALID_RESYNCS in a row. Stopping sync.
If you connected an Amazon WorkMail account to Nylas using IMAP, you might see your account in a Stopped state and see an error in the mailsync logs like the error above. The error message indicates that the email server does not maintain consistent UIDVALIDITY
values, which is incompatible with Nylas.
You might be able to solve this issue by authenticating your Amazon WorkMail account using Microsoft Exchange’s advanced login settings and specifying one of the following server addresses, depending on your account region:
mobile.mail.eu-west-1.awsapps.com
mobile.mail.us-west-2.awsapps.com
mobile.mail.us-east-1.awsapps.com
Unsupported providers
Due to latency and errors with UID
, the Vodaphone IMAP provider is not supported.