I get a 404 error when I try to download a route with the app. I had success using the mobile website.

It's working OK for us here Michael. Can you share further details as it may relate to specific circumstances? In particular, what device you're using (iPhone/Android), what route you're downloading and what download settings you've chosen.

I'm using an android phone.

I've tried a number of does without success, and have not found one that works. Here is one that fails too download from the app.

https://www.plotaroute.com/route/1495950?units=miles

I tried to download by selecting the fit icon on the route info page. 

We've tried downloading a FIT file for that route with the app on an Android device and it worked OK for us. You should see something like this:

Do you have possibly any apps or browser plug-ins installed that could be blocking the download? It would be worth clearing the app's cache (on your My Settings page in the plotaroute app) to see if this helps or uninstalling the app and reinstalling it. I'm not sure what else to suggest.

I cleared the cache which didn't help. When I select the download button I get this error.

Just to test, I went to https://www.plotaroute.com/route/1495950?units=miles from my PC using Chrome, logged in. Downloaded the .fit file ok, loaded in a local PC app.

I am in the UK.

That's very odd, as we can't reproduce this on an Android phone here, which makes it hard to resolve.

Did you try uninstalling and reinstalling the app?

And do you have any other apps installed that could be intefering with the download request? 

And just to be sure, you're saying it works OK if you do the same thing from the following page in Chrome on your Android device?

  https://www.plotaroute.com/mobile/route/1495950

I removed the app and now I do not get prompted to install it when i navigate to the website on my mobile. Now I'm even more frustrated.

I'm not using any apps taht would interfere with the download request.

I do not use Chrome. I can successfully download with my browser.

Can you try to install the app with Chrome as not all browsers have full support for Progressive Web Apps?

I do not have, and do not want, chrome on my phone.

I use wikiloc app for trails. Plotaroute is a fabulous tool for plotting routes which I would download the gpx file to wikiloc by default. This no longer appears to work. Has there been a format change which resulted in this error. The apps greatly complement one another...

We haven't made any format changes to our GPX downloads recently, so perhaps something has changed at wikiloc. We've just tried it here and had no problems importing a route from plotaroute to wikiloc in GPX format. I'd recommend contacting wikiloc to see if they can help, as we have no way of knowing why they're rejecting your file.