diff --git a/scenarios/sanity/sipp_scenario00_test.yml.tt2 b/scenarios/sanity/sipp_scenario00_test.yml.tt2
index 8aa81d54..b491d556 100644
--- a/scenarios/sanity/sipp_scenario00_test.yml.tt2
+++ b/scenarios/sanity/sipp_scenario00_test.yml.tt2
@@ -11,7 +11,7 @@ messages:
   - 'CSeq: \d+ REGISTER'
   - 'Server: Sipwise NGCP LB'
   - 'Content-Length:\s+0'
-- - 'SIP/2.0 400 Invalid To Header'
+- - 'SIP/2.0 400 I[n]?valid To Header'
   - 'From: <sip:[% scenarios.0.responders.0.username %]@sanity.scenarios.test>;tag=[\w-]+'
   - 'To: 500;tag=[\w-]+'
   - 'CSeq: \d+ REGISTER'