Two Labels in one graph and error with axis titles

[noroxi7]

Hi there I have two question:

First, how can I set two labels, one for line and another one for a scatter, as you see, I have a combined graph (line and scatter), how can i set two labels?

Second: I don't know why, but when i put titles in x and y axis I get an error like this:

Uncaught RangeError: invalid digits value: NaN
Fi https://cdn.jsdelivr.net/npm/chart.js:13
Fi https://cdn.jsdelivr.net/npm/chart.js:13
numeric https://cdn.jsdelivr.net/npm/chart.js:13
Q https://cdn.jsdelivr.net/npm/chart.js:13
generateTickLabels https://cdn.jsdelivr.net/npm/chart.js:13
_convertTicksToLabels https://cdn.jsdelivr.net/npm/chart.js:13
update https://cdn.jsdelivr.net/npm/chart.js:13
Ke https://cdn.jsdelivr.net/npm/chart.js:13
update https://cdn.jsdelivr.net/npm/chart.js:13
_updateLayout https://cdn.jsdelivr.net/npm/chart.js:13
update https://cdn.jsdelivr.net/npm/chart.js:13
eo https://cdn.jsdelivr.net/npm/chart.js:13
file:///home/---/--/--/--/----/---/main.js:318
chart.js:13:47878

Line 318 ia this: var myChart9 = new Chart(ctx9, {

The funny it is that when i put title in just one axis, i don't get an error, and when I try putting in others graph they works, so I don't know what is wrong.

Browser: Firefox Browser version 89.0.2 (64-bit)

Script in html:
<script src="https://code.jquery.com/jquery-3.3.1.js"></script> <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
Here is the code .js:
var myChart9 = new Chart(ctx9, { type: 'line', data: { labels: tempTable, datasets: [{ label: 'Humedad Absoluta', type: "line", borderColor: "#3e95cd", data:humAbsoTable, fill: false, cubicInterpolationMode: 'monotone', tension: 0.4, },{ label: 'Actual', data: [,,0.023], backgroundColor: 'rgba(255, 99, 132, 0.3)', borderColor: 'rgba(255, 99, 132, 1)', borderWidth: 1, type:"scatter", radius: 7 }] }, options: { scales: { x:{ ticks:{ maxTicksLimit:15 } }, y: { beginAtZero: true, ticks:{ maxTicksLimit:15 }, display: true, title: { display: true, text: 'Humedad Absoluta (KgVap/KgAS)', font: { family: 'Helvetica Neue', size: 13, style: 'normal', lineHeight: 1.2 }, } } }, plugins: { legend:false, title: { display: true, text: 'Huemdad y Temperatura', font: { family: 'Helvetica Neue', size: 15, weight:'lighter', lineHeight: 1.2 } }, tooltip: { enabled:false, callbacks: { label: (item) => item.dataset.label + ': ' + formatter.format(item.parsed.y), } } } } });

[LeeLenaleee]

You can just add a second x axis for labels for your other dataset, also your title for both axis works fine: https://jsfiddle.net/Leelenaleee/g34c5jrq/4/