TLS encryption was requested, but your Sieve server does not advertise TLS in its capabilities. You can choose to try to initiate TLS negotiations nonetheless, or cancel the operation.
Iarradh criptiú TLS, ach ní mhaíonn do fhreastalaí Sieve go dtacaíonn sé le TLS. Is féidir caibidlí TLS a thosú mar sin féin, nó an oibríocht a chealú.