It appeared that my IFTTT applet I use to publish my Instagram photos to Twitter was broken.
I use the Applet, Tweet your Instagrams as native photos on Twitter which takes an instagram posting, posts the image to Twitter. You can share your Instagram postings automatically to Twitter from Instagram, but back in the day this would only post a link. So rather than post each image manually to Twitter I used IFTTT to do this automatically. It had been working fine for years, but recently stopped working. I did get a notification, so I went into IFTTT disconnected and reconnected the applet. I then posted an image to Instagram to check it was working.
Got me thinking I might want to see how IFTTT an worth with Mastodon. Though I do intend to wait and see how Mastodon fares, and if auto-posting is a thing there.