diff --git a/src/chunk_insert_state.c b/src/chunk_insert_state.c
index f8200dd8f..e99bba73f 100644
--- a/src/chunk_insert_state.c
+++ b/src/chunk_insert_state.c
@@ -465,10 +465,21 @@ set_arbiter_indexes(ChunkInsertState *state, ChunkDispatch *dispatch)
 
 		if (ts_chunk_index_get_by_hypertable_indexrelid(chunk, hypertable_index, &cim) < 1)
 		{
-			elog(ERROR,
-				 "could not find arbiter index for hypertable index \"%s\" on chunk \"%s\"",
-				 get_rel_name(hypertable_index),
-				 get_rel_name(RelationGetRelid(state->rel)));
+			/*
+			 * In case of distributed hypertables, we don't have information about the
+			 * arbiter index on the remote side, so error out with a helpful hint
+			 */
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("could not find arbiter index for hypertable index \"%s\" on chunk "
+							"\"%s\"",
+							get_rel_name(hypertable_index),
+							get_rel_name(RelationGetRelid(state->rel))),
+					 hypertable_is_distributed(dispatch->hypertable) ?
+						 errhint(
+							 "Omit the index inference specification for the distributed hypertable"
+							 " in the ON CONFLICT clause.") :
+						 0));
 		}
 
 		state->arbiter_indexes = lappend_oid(state->arbiter_indexes, cim.indexoid);
diff --git a/tsl/src/data_node_dispatch.c b/tsl/src/data_node_dispatch.c
index 030174e86..e13e58ba4 100644
--- a/tsl/src/data_node_dispatch.c
+++ b/tsl/src/data_node_dispatch.c
@@ -1090,7 +1090,10 @@ plan_remote_insert(PlannerInfo *root, DataNodeDispatchPath *sdpath)
 	if (onconflict == ONCONFLICT_NOTHING)
 		do_nothing = true;
 	else if (onconflict != ONCONFLICT_NONE)
-		elog(ERROR, "unexpected ON CONFLICT specification: %d", (int) onconflict);
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ON CONFLICT DO UPDATE not supported"
+						" on distributed hypertables")));
 
 	userid = OidIsValid(rte->checkAsUser) ? rte->checkAsUser : GetUserId();
 
diff --git a/tsl/src/fdw/modify_plan.c b/tsl/src/fdw/modify_plan.c
index f5deb21fc..4a5082b00 100644
--- a/tsl/src/fdw/modify_plan.c
+++ b/tsl/src/fdw/modify_plan.c
@@ -136,7 +136,10 @@ fdw_plan_foreign_modify(PlannerInfo *root, ModifyTable *plan, Index result_relat
 	if (plan->onConflictAction == ONCONFLICT_NOTHING)
 		do_nothing = true;
 	else if (plan->onConflictAction != ONCONFLICT_NONE)
-		elog(ERROR, "unexpected ON CONFLICT specification: %d", (int) plan->onConflictAction);
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ON CONFLICT DO UPDATE not supported"
+						" on distributed hypertables")));
 
 	/*
 	 * Core code already has some lock on each rel being planned, so we can
diff --git a/tsl/test/expected/dist_hypertable-11.out b/tsl/test/expected/dist_hypertable-11.out
index 07ca48609..a4b28e3fc 100644
--- a/tsl/test/expected/dist_hypertable-11.out
+++ b/tsl/test/expected/dist_hypertable-11.out
@@ -1147,11 +1147,19 @@ Sun Sep 03 06:18:00 2017 PDT|     9| 8.7|    3
 (1 row)
 
 \set ON_ERROR_STOP 0
--- ON CONFLICT only works with DO NOTHING
+-- ON CONFLICT DO NOTHING only works when index inference is omitted
+\set VERBOSITY default
+INSERT INTO disttable
+VALUES ('2017-09-02 06:09', 6)
+ON CONFLICT(time,device) DO NOTHING;
+ERROR:  could not find arbiter index for hypertable index "disttable_pkey" on chunk "_dist_hyper_1_9_chunk"
+HINT:  Omit the index inference specification for the distributed hypertable in the ON CONFLICT clause.
+\set VERBOSITY terse
+-- ON CONFLICT only works with DO NOTHING for now
 INSERT INTO disttable (time, device, "Color", temp)
 VALUES ('2017-09-09 08:13', 7, 3, 27.5)
 ON CONFLICT (time) DO UPDATE SET temp = 3.2;
-ERROR:  unexpected ON CONFLICT specification: 2
+ERROR:  ON CONFLICT DO UPDATE not supported on distributed hypertables
 -- Test that an INSERT that would create a chunk does not work on a
 -- data node
 SELECT * FROM test.remote_exec(ARRAY[:'DATA_NODE_1'], $$
diff --git a/tsl/test/expected/dist_hypertable-12.out b/tsl/test/expected/dist_hypertable-12.out
index 6c91bc052..61346c32a 100644
--- a/tsl/test/expected/dist_hypertable-12.out
+++ b/tsl/test/expected/dist_hypertable-12.out
@@ -1147,11 +1147,19 @@ Sun Sep 03 06:18:00 2017 PDT|     9| 8.7|    3
 (1 row)
 
 \set ON_ERROR_STOP 0
--- ON CONFLICT only works with DO NOTHING
+-- ON CONFLICT DO NOTHING only works when index inference is omitted
+\set VERBOSITY default
+INSERT INTO disttable
+VALUES ('2017-09-02 06:09', 6)
+ON CONFLICT(time,device) DO NOTHING;
+ERROR:  could not find arbiter index for hypertable index "disttable_pkey" on chunk "_dist_hyper_1_9_chunk"
+HINT:  Omit the index inference specification for the distributed hypertable in the ON CONFLICT clause.
+\set VERBOSITY terse
+-- ON CONFLICT only works with DO NOTHING for now
 INSERT INTO disttable (time, device, "Color", temp)
 VALUES ('2017-09-09 08:13', 7, 3, 27.5)
 ON CONFLICT (time) DO UPDATE SET temp = 3.2;
-ERROR:  unexpected ON CONFLICT specification: 2
+ERROR:  ON CONFLICT DO UPDATE not supported on distributed hypertables
 -- Test that an INSERT that would create a chunk does not work on a
 -- data node
 SELECT * FROM test.remote_exec(ARRAY[:'DATA_NODE_1'], $$
diff --git a/tsl/test/expected/dist_hypertable-13.out b/tsl/test/expected/dist_hypertable-13.out
index d9ef66830..ae491899d 100644
--- a/tsl/test/expected/dist_hypertable-13.out
+++ b/tsl/test/expected/dist_hypertable-13.out
@@ -1146,11 +1146,19 @@ Sun Sep 03 06:18:00 2017 PDT|     9| 8.7|    3
 (1 row)
 
 \set ON_ERROR_STOP 0
--- ON CONFLICT only works with DO NOTHING
+-- ON CONFLICT DO NOTHING only works when index inference is omitted
+\set VERBOSITY default
+INSERT INTO disttable
+VALUES ('2017-09-02 06:09', 6)
+ON CONFLICT(time,device) DO NOTHING;
+ERROR:  could not find arbiter index for hypertable index "disttable_pkey" on chunk "_dist_hyper_1_9_chunk"
+HINT:  Omit the index inference specification for the distributed hypertable in the ON CONFLICT clause.
+\set VERBOSITY terse
+-- ON CONFLICT only works with DO NOTHING for now
 INSERT INTO disttable (time, device, "Color", temp)
 VALUES ('2017-09-09 08:13', 7, 3, 27.5)
 ON CONFLICT (time) DO UPDATE SET temp = 3.2;
-ERROR:  unexpected ON CONFLICT specification: 2
+ERROR:  ON CONFLICT DO UPDATE not supported on distributed hypertables
 -- Test that an INSERT that would create a chunk does not work on a
 -- data node
 SELECT * FROM test.remote_exec(ARRAY[:'DATA_NODE_1'], $$
diff --git a/tsl/test/sql/dist_hypertable.sql.in b/tsl/test/sql/dist_hypertable.sql.in
index 7cc920f9d..dd6bd40c2 100644
--- a/tsl/test/sql/dist_hypertable.sql.in
+++ b/tsl/test/sql/dist_hypertable.sql.in
@@ -365,7 +365,15 @@ $$);
 
 
 \set ON_ERROR_STOP 0
--- ON CONFLICT only works with DO NOTHING
+
+-- ON CONFLICT DO NOTHING only works when index inference is omitted
+\set VERBOSITY default
+INSERT INTO disttable
+VALUES ('2017-09-02 06:09', 6)
+ON CONFLICT(time,device) DO NOTHING;
+\set VERBOSITY terse
+
+-- ON CONFLICT only works with DO NOTHING for now
 INSERT INTO disttable (time, device, "Color", temp)
 VALUES ('2017-09-09 08:13', 7, 3, 27.5)
 ON CONFLICT (time) DO UPDATE SET temp = 3.2;