diff --git a/tmt/steps/report/reportportal.py b/tmt/steps/report/reportportal.py
index 6b08daf364..489e176ad9 100644
--- a/tmt/steps/report/reportportal.py
+++ b/tmt/steps/report/reportportal.py
@@ -36,6 +36,13 @@ def _str_env_to_default(option: str, default: Optional[str]) -> Optional[str]:
     return str(os.getenv(env_var))
 
 
+def _filter_invalid_chars(data: str) -> str:
+    return re.sub(
+        '[^\u0020-\uD7FF\u0009\u000A\u000D\uE000-\uFFFD\U00010000-\U0010FFFF]+',
+        '',
+        data)
+
+
 @dataclasses.dataclass
 class ReportReportPortalData(tmt.steps.report.ReportStepData):
 
@@ -226,13 +233,14 @@ class ReportReportPortal(tmt.steps.report.ReportPlugin[ReportReportPortalData]):
     def handle_response(self, response: requests.Response) -> None:
         """ Check the endpoint response and raise an exception if needed """
 
-        if not response.ok:
-            raise tmt.utils.ReportError(
-                f"Received non-ok status code from ReportPortal: {response.text}")
-
         self.debug("Response code from the endpoint", response.status_code)
         self.debug("Message from the endpoint", response.text)
 
+        if not response.ok:
+            raise tmt.utils.ReportError(
+                f"Received non-ok status code {response.status_code} "
+                f"from ReportPortal: {response.text}")
+
     def check_options(self) -> None:
         """ Check options for known troublesome combinations """
         # TODO: Update restriction of forbidden option combinations based on feedback.
@@ -393,7 +401,13 @@ def go(self, *, logger: Optional[tmt.log.Logger] = None) -> None:
             suite_description += f"<br>{self.data.artifacts_url}"
 
         # Communication with RP instance
-        with tmt.utils.retry_session() as session:
+        with tmt.utils.retry_session(status_forcelist=(
+                429,   # Too Many Requests
+                500,   # Internal Server Error
+                502,   # Bad Gateway
+                503,   # Service Unavailable
+                504,   # Gateway Timeout
+                )) as session:
 
             if create_launch:
 
@@ -528,7 +542,7 @@ def go(self, *, logger: Optional[tmt.log.Logger] = None) -> None:
                         response = session.post(
                             url=f"{self.get_url()}/log/entry",
                             headers=self.get_headers(),
-                            json={"message": log,
+                            json={"message": _filter_invalid_chars(log),
                                   "itemUuid": item_uuid,
                                   "launchUuid": launch_uuid,
                                   "level": level,
@@ -537,7 +551,7 @@ def go(self, *, logger: Optional[tmt.log.Logger] = None) -> None:
 
                         # Write out failures
                         if index == 0 and status == "FAILED":
-                            message = result.failures(log)
+                            message = _filter_invalid_chars(result.failures(log))
                             response = session.post(
                                 url=f"{self.get_url()}/log/entry",
                                 headers=self.get_headers(),