diff --git a/bin/tests/system/doth/tests.sh b/bin/tests/system/doth/tests.sh
index 052e2272f9..2c5c75f1db 100644
--- a/bin/tests/system/doth/tests.sh
+++ b/bin/tests/system/doth/tests.sh
@@ -854,7 +854,7 @@ status=$((status + ret))
 
 # check whether we can use curl for sending test queries.
 if [ -x "${CURL}" ] ; then
-	CURL_HTTP2="$(${CURL} --version | grep -E '^Features:.* HTTP2( |$)')"
+	CURL_HTTP2="$(${CURL} --version | grep -E '^Features:.* HTTP2( |$)' || true)"
 
 	if [ -n "$CURL_HTTP2" ]; then
 		testcurl=1
@@ -870,7 +870,7 @@ if [ -n "$testcurl" ]; then
 	echo_i "checking max-age for positive answer ($n)"
 	ret=0
 	# use curl to query for 'example/SOA'
-	$CURL -kD headers.$n "https://10.53.0.1:${HTTPSPORT}/dns-query?dns=AAEAAAABAAAAAAAAB2V4YW1wbGUAAAYAAQ" > /dev/null 2>&1
+	$CURL -kD headers.$n "https://10.53.0.1:${HTTPSPORT}/dns-query?dns=AAEAAAABAAAAAAAAB2V4YW1wbGUAAAYAAQ" > /dev/null 2>&1 || ret=1
 	grep "cache-control: max-age=86400" headers.$n > /dev/null || ret=1
 	if [ $ret != 0 ]; then echo_i "failed"; fi
 	status=$((status + ret))
@@ -879,7 +879,7 @@ if [ -n "$testcurl" ]; then
 	echo_i "checking max-age for negative answer ($n)"
 	ret=0
 	# use curl to query for 'fake.example/TXT'
-	$CURL -kD headers.$n "https://10.53.0.1:${HTTPSPORT}/dns-query?dns=AAEAAAABAAAAAAAABGZha2UHZXhhbXBsZQAAEAAB" > /dev/null 2>&1
+	$CURL -kD headers.$n "https://10.53.0.1:${HTTPSPORT}/dns-query?dns=AAEAAAABAAAAAAAABGZha2UHZXhhbXBsZQAAEAAB" > /dev/null 2>&1 || ret=1
 	grep "cache-control: max-age=3600" headers.$n > /dev/null || ret=1
 	if [ $ret != 0 ]; then echo_i "failed"; fi
 	status=$((status + ret))