diff --git a/cli/server.go b/cli/server.go
index 548f350bae9bc..59b46a5726d75 100644
--- a/cli/server.go
+++ b/cli/server.go
@@ -2565,6 +2565,8 @@ func parseExternalAuthProvidersFromEnv(prefix string, environ []string) ([]coder
 	return providers, nil
 }
 
+var reInvalidPortAfterHost = regexp.MustCompile(`invalid port ".+" after host`)
+
 // If the user provides a postgres URL with a password that contains special
 // characters, the URL will be invalid. We need to escape the password so that
 // the URL parse doesn't fail at the DB connector level.
@@ -2573,7 +2575,11 @@ func escapePostgresURLUserInfo(v string) (string, error) {
 	// I wish I could use errors.Is here, but this error is not declared as a
 	// variable in net/url. :(
 	if err != nil {
-		if strings.Contains(err.Error(), "net/url: invalid userinfo") {
+		// Warning: The parser may also fail with an "invalid port" error if the password contains special
+		// characters. It does not detect invalid user information but instead incorrectly reports an invalid port.
+		//
+		// See: https://github.com/coder/coder/issues/16319
+		if strings.Contains(err.Error(), "net/url: invalid userinfo") || reInvalidPortAfterHost.MatchString(err.Error()) {
 			// If the URL is invalid, we assume it is because the password contains
 			// special characters that need to be escaped.
 
diff --git a/cli/server_internal_test.go b/cli/server_internal_test.go
index 4bdf54f4f0583..b5417ceb04b8e 100644
--- a/cli/server_internal_test.go
+++ b/cli/server_internal_test.go
@@ -351,13 +351,23 @@ func TestEscapePostgresURLUserInfo(t *testing.T) {
 			output: "",
 			err:    xerrors.New("parse postgres url: parse \"postgres://local host:5432/coder\": invalid character \" \" in host name"),
 		},
+		{
+			input:  "postgres://coder:co?der@localhost:5432/coder",
+			output: "postgres://coder:co%3Fder@localhost:5432/coder",
+			err:    nil,
+		},
+		{
+			input:  "postgres://coder:co#der@localhost:5432/coder",
+			output: "postgres://coder:co%23der@localhost:5432/coder",
+			err:    nil,
+		},
 	}
 	for _, tc := range testcases {
 		tc := tc
 		t.Run(tc.input, func(t *testing.T) {
 			t.Parallel()
 			o, err := escapePostgresURLUserInfo(tc.input)
-			require.Equal(t, tc.output, o)
+			assert.Equal(t, tc.output, o)
 			if tc.err != nil {
 				require.Error(t, err)
 				require.EqualValues(t, tc.err.Error(), err.Error())