I received an unsolicited email from Google.

Search Console has identified that your site is affected by 1 new Mobile Usability related issue. This means that Mobile Usability may be negatively affected in Google Search results. We encourage you to fix this issue.
New issue found:

Content wider than screen

I have 480px and 980px widths for the site, and I don't notice any issues with it.
I don't need any SEO as it's a site for work and not for sales.
Is there something I should look at?