.fit file not uploading

Hi

I have a ride that I saved on my Garmin Connect 810.

It did not upload to Garmin Connect automatically once I finished the ride and saved it.

When this happens (which is fairly often), I find the file on my computer and manually upload it, but this time I get an error message: "One of your files was not accepted by the system. Please contact Support for assistance."

The ride shows on my Garmin Connect under All Rides (it's the 122km ride on Sun 4 May - I can share a photo if needed), but when I click on it (to see summary, map etc), nothing happens.

The file is 172 KB. I'm happy to share that too - there doesn't seem to be an option here.

Thanks a lot to anyone who can help
Justin