diff --git a/tmt/steps/report/reportportal.py b/tmt/steps/report/reportportal.py
index 7c6418050e..1500a34e15 100644
--- a/tmt/steps/report/reportportal.py
+++ b/tmt/steps/report/reportportal.py
@@ -40,7 +40,7 @@ def _filter_invalid_chars(data: str) -> str:
     return re.sub(
         '[^\u0020-\uD7FF\u0009\u000A\u000D\uE000-\uFFFD\U00010000-\U0010FFFF]+',
         '',
-        data)
+        data).encode("utf-8", errors="ignore").decode("utf-8")
 
 
 @dataclasses.dataclass