fix: SocketError: getaddrinfo: for imap channels (#5824)

fixes: #5431

lib/exception_list.rb

@@ -1,3 +1,5 @@
+require 'net/imap'
+
 module ExceptionList
   REST_CLIENT_EXCEPTIONS = [RestClient::NotFound, RestClient::GatewayTimeout, RestClient::BadRequest,
                             RestClient::MethodNotAllowed, RestClient::Forbidden, RestClient::InternalServerError,
@@ -8,4 +10,10 @@ module ExceptionList
   SMTP_EXCEPTIONS = [
     Net::SMTPSyntaxError
   ].freeze
+
+  IMAP_EXCEPTIONS = [
+    Errno::ECONNREFUSED, Net::OpenTimeout, Net::IMAP::NoResponseError,
+    Errno::ECONNRESET, Errno::ENETUNREACH, Net::IMAP::ByeResponseError,
+    SocketError
+  ].freeze
 end