Hi,

This issue is resolve 

In Odoo17 render method doesn't work like above way you need to add this way below.

@api.depends('message', 'scheduled_date', 'image_ids')
def _compute_twitter_preview(self):
    for post in self:
        template = self.env.ref('social_medias.twitter_preview').id
        values = {
            'message': post.message,
            'images': [
                image.datas if not image.id
                else base64.b64encode(open(image._full_path(image.store_fname), 'rb').read()) for image in post.image_ids
            ]
        }
        post.twitter_preview = self.env['ir.qweb']._render(template, values)

You need to use 

self.env['ir.qweb']._render(template, values)

and add xml_id of that specific template and second argument is dict of values.

i refer odoo addons ir.ui.view.py file like this way

Its complete work.

Thanks.