Not sure what I'm doing wrong, but when I'm on an approach, I hit the "approach" button on the AP, but the plane does not start capture the glideslope.  I usually have to kick off the AP and hand fly it.  Any ideas why this would happen?

do you capture from below?

It works just fine for me. Without knowing how you operate the plane, it's hard to pinpoint where the error lies.

The Longitude is one of the best in many phases and, for the most part, I've had few issues with GS or GP capture.

Is this an ILS or an RNAV type of approach?  I've found GP captures in RNAV approaches require that you be at the Minimum Approach Altitude prior to the FAF.  Also, it's a good idea with an RNAV approach to set the altitude at or just above field elevation prior to activating the coupled approach, so that it is "allowed" to descend.

With an ILS, if I activate the approach before the IAF and I descend to the Minimum prior to the IF it will capture.

Sometimes, even when you do everything right, an RNAV GP will drop down without coupling.  If I see that happen, I make sure APPR is active, then I set a VS of about 800 fpm so that I descend to the GP - when I intersect with the GP, the AP couples and the approach proceeds normally.

If I recall, I usually hit the APP button slightly before the IAF.  Maybe that's too soon?  In most cases, I activate it while still above the glideslope.  Instead of intercepting it, the plane will keep flying the approach, but won't capture the GS.

So, just did an ILS into KCVG and I hit APPR, but the plane did not react.  In the past, if I had appr mode activated, it'd pitch down once I reached the glideslope.  Now, it just blows right through it and I end up high if I don't manually take over.  Not sure why it worked before but stopped recently.  I accidentally "upgraded" to Win 11, so I had to revert back to 10.  When I launched MSFS after that, it seemed to reset all my settings.  Not sure why that would affect the AP, but something's wonky.

When making a Localizer approach I will sometimes initiate the coupled approach prior to the IAF while I am still above the charted intercept altitude (something that will not work for some RNAV approaches). You basically want to be at the minimum altitude at full approach configuration before intercepting the glideslope (at final approach speed, gear down and flaps in final position).

One thing I would ask is if you've verified that you are in LOC mode when on the final track and before the GS intercept?  If you're still in FMS mode and the AP has not switched over to LOC it will not descend on the GS.

Even though this should happen automatically, if the aircraft has turned on final but has not switched to LOC within a reasonable period of time, I will force its hand by switching manually.

Thanks.  Yeah, I've noticed in the past that it automatically switches from FMS to LOC1, but I manually switched to the LOC this evening.  Nothing.  Clicking the approach button did nothing, either.  Lately, I just get frustrated and hand fly it in.  I've also noticed that sometimes after I takeoff, I'll turn toward my desired course, and once I'm close, I'll kick on the AP and press the NAV button.  It appears to start intercepting the correct course, but sometime the plane will just fly in a big circle.  Weird behavior...

Are you in green needles?

ILS frequency tuned in?

Are you intercepting the LOC before you intercept the glideslope?

Usually, I just leave it on the FMS, but it turns green and changes to LOC when intercepting.  Everything else seems to work normally.  It flies all the waypoints on the approach, but it seems to just totally ignore the GS.  Checked last night to make sure the freq was correct for the approach, and it was.  Sometimes when I'm on an approach, I'll set the altitude I want and use VS with a decent descent rate to get down to where I need to be.  That wouldn't mess anything up, would it?

All I know is, for the most part, it was working fine before I had to revert to Win10.  After that, MSFS wouldn't even launch.  I finally got it running, but all my graphics settings were reset.  I wonder if some other setting went haywire?  I get lots of results when I google MSFS2020 not intercepting glideslope for various aircraft, but no real solution yet.  I may try to make a video at some point.