diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8671b130..665fcbe1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 * Builtin Prosody: optional settings to change the url for Prosody's API calls.
 * Diagnostic tool: testing API communication from Peertube to Prosody.
 * Diagnostic tool: testing API communication from Prosody to Peertube.
+* Diagnostic tool: correctly parse Prosody nightly build versions.
 
 ## v3.0.0
 
diff --git a/server/lib/diagnostic/prosody.ts b/server/lib/diagnostic/prosody.ts
index 4fb84785..f069eb54 100644
--- a/server/lib/diagnostic/prosody.ts
+++ b/server/lib/diagnostic/prosody.ts
@@ -74,7 +74,7 @@ export async function diagProsody (test: string, options: RegisterServerOptions)
     return result
   }
 
-  const versionMatches = about.match(/^Prosody\s*(\d+)\.(\d+)\.(\d+)\s*$/mi)
+  const versionMatches = about.match(/^Prosody\s*(\d+)\.(\d+)(?:\.(\d+)| (nightly build \d+.*))\s*$/mi)
   if (!versionMatches) {
     result.messages.push({
       level: 'error',
@@ -84,7 +84,7 @@ export async function diagProsody (test: string, options: RegisterServerOptions)
   } else {
     const major = versionMatches[1]
     const minor = versionMatches[2]
-    const patch = versionMatches[3]
+    const patch = versionMatches[3] ?? versionMatches[4]
     result.messages.push(`Prosody version is ${major}.${minor}.${patch}`)
     if (major !== '0' && minor !== '11') {
       result.messages.push({