Hello @Miklo78
Thanks for posting and apologies for any confusion over this. Only activities recorded with the Apple Watch Workout app recorded within the past 30 days are able to sync to Strava. Activities uploaded to the Health app from a third party (such as Fitify) will not sync to Strava.
Visit this link for more info about Apple Health and Strava
I'm not familiar with Fitify, but you could investigate if it's possible to upload your Fitify data directly to Strava. The first thing i would do is contact Fitify directly, in case they have used our API to build a way to sync data directly to Strava. To provide some context, we have a publicly available API that hundreds of external developers use to integrate with Strava data. These integrations are built and maintained by those 3rd party developers which means that any questions are better directed their way.
If that's not a possibility, you could look into file uploads. If you can export your data from Fitify in one of our supported file formats: .fit, .tcx or .gpx, you may be able to upload those files to Strava.
More information here
I've emailed Fitify support, so we'll see what they say. Thanks.