PDF export of invoices etc. no longer working

I am running ERPNext on the Frappe cloud. Until a couple of days ago I had no issues exporting invoices, sales orders etc. as PDF, however now it will sit and time out most of the time. Every so often it succeeds, but this is very rare. I have not made any changes to the print format and have applied all outstanding updates in the Frappe dashboard.

The Frappe dashboard logs show warnings for wkhtmltopdf as follows:

Fontconfig warning: "/etc/fonts/conf.d/45-latin.conf", line 23: Having multiple <family> in <alias> isn't supported and may not work as expected

The file and line numbers vary (e.g. "/etc/fonts/conf.d/40-nonlatin.conf", line 93) but this is the only warning.

As mentioned, I did not make any changes before this problem started to occur. Trying to export old invoices that previously worked suffer the same issue, so it is not something added to new invoices.

Thanks for any help, I am really stuck with this!