Why does my biking activities not compile in intensive minutes?

That is the strange thing. I wore my hrm and when I consult the activities report, I can see that the data is there. It seems that it just doesn't sync with garmin connect.

That is the strange thing. I wore my hrm and when I consult the activities report, I can see that the data is there. It seems that it just doesn't sync with garmin connect.

I do not quite understand what you mean - the screenshots you posted, do show the HR and intensity minutes from yesterday, so it seems to work.

As you can see from the screenshots, I did activities on the 4th trough the 9th. The activities on May 6 and May 7 were really intense, as you can see from the training effect. But on the two last pictures, you can see that there are only data for May 8-9th in Garmin connect. The frequencies for the previous days don't appear even tough I wore my watch and did intense activities that were recorded. Do you understand better my point?

Any thoughts?

Do you understand better my point?

Not really. On the screenhsots, I see an activity with a HR graph and with training status, but without any date. Then I see a calendar showing you did activites from 4th to 9th, but it does not tell whether the HR was recorded or not. And then there is the 3rd screenshot with the HR that clearly demonstrates, there was no HR recorded since 3rd May to 7th May. And the final screenshot shows the intensivity minutes only for 9th May, which seems to be perfectly matching the missing HR from 3rd to 7th May. And on 8th May the max HR was pretty low, hence it is not surprising at all, that you did not get any intensity minutes for that day.

So far, I cannot advise anything else than I already did - you need the HR to get the intensity minutes (with the above mentioned exceptions of intensity minutes calculated on devices without a HRM, which is not your case). So if there was no HR detected during several days, there cannot be any intensity minutes either.

If the HRM does not work, or does not sync, you need to fix the HRM problem first. If the HRM was disabled, you need to enable it. If it was caused by a bad fit of the wristband, you need to adjust it. If the sensor was dirty, you need to clean it. If you had a strong periferal vasoconstriction during several days, wear a HRM chest belt instead. If the watch is defectuous, have it replaced (though it seems to be working now, so it does not seem to be the case). Etc., etc. However as long as you do not have any HR data, you will have no intensity minutes either.

Thank you for your kind answer, but I understand that my explanations might not be complete. The activity showing heartrate and training effect in the first screenshot was performed on May 7. What I mean, is that for the activities that are logged in the calendar (second screenshot), I wore my hrm and it worked, as showed by the heartrate reading of the activity (first screenshot), but for an unexplained reason, it seems all my heartrate data from May 3 trough 8 have disappeared, as showed on the third screenshot. Hence, the activities are not considered in intensity minutes, as showed by the fourth screenshot. My question is, what happened with the data for the rest of the week? And even though it disappeared from the report of the week, why is the intensity minutes showed in the first screenshot not taken into account? I wore my hrm during my activities, and when I consult the activity report, the information is there. Furthermore, I wore my watch all those days, all day long, as usual. I'm just trying to understand what is the glitch. I'm guessing it is with the app or the sync because the heartrate reading of the watch works, my hrm works, it is just that data disappeared. Is this unheard-of? Thanks for your help.

OK, now it is explained clearer, and now I understand what you mean.

My question is, what happened with the data for the rest of the week?

I do not know, but there are two basic possibilities: the more probable possibility is that you have your device associated with more than one account, and hence some data is sometimes stored into the wrong account. This happens more frequently than you would believe, and people are never aware of it, and often do not want to admit such possibility. It mostly happens when the user reinstalls the app, or starts using it on a new phone, and while installing it, they inadvertently sign up instead of signing in. You can read how to fix such case in the document Data is Missing from My Garmin Account After Syncing 

Another possibility is that the data FIT file storing the daily HR data got corrupted. Activity files contain own HR data, independently on the daily HR data, so the loss of the daily HR data would not remove the HR data from the activity.

why is the intensity minutes showed in the first screenshot not taken into account?

There are no intensity minutes shown on the first screenshot. There is just the training effect (not related to intensity minutes) and the activity HR data. The intensity minutes are not available for exactly the same reason as I wrote above about the HR.