When trying to create an IMAP Mailbox Sync via Office 365 , I was getting the following Failed Error next to the Sync Status
TLS negotiation failed with status AlgorithmMismatch
The IMAP Server I was syncing from was using SSL on port 993 however the SSL cert was self signed rather than from a proper cert authority
In the end I had to enable syncing through 143 Uncrypted or you can purchase a sign SSL cert for the migration
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