Huge drop after domain migration. Don't know the cause. Am I missing something?

Did you verify your migration via Google Search Console?

Google still didn't realize that these URLs are moved.

site: command will continue to work on old redirected domains, it doesn't mean anything is wrong.

When I check the cache on each of those redirected urls it correctly reflects the new canonical so Google has seen and processed the redirect.

 

I don't see anything obvious amiss. 

 

in your log files are you seeing ANY 200 headers on the old domain? If any old content is orphaned there Google will struggle to process the domain change. 

 

Any other anomalies in log files?

 

When did the other domains move? same time? 

etc.

 

 

 

I did this from the beginning, also the 301 redirects. So it's quite strange then...

Google has found your redirect . I don't think there is any issue in site move process.

May be other ranking updates have decreased the ranking .. tough to say without going to content and related keywords

I will check the log files. I have not done this yet.

The other domains are moved to vihara.nl (the old domain) some years ago. But I changed it all to the new domain on the same day of the migration.

I see 200 headers from the old domain in the log files, see some below.

Do you know how I can figure out what's causing this and how I can solve this?

File logs with 200 header old domain:

Hmmm. 

Its not good practice to only check Google analytics traffic and assume that everything is wrong. 

Can you please go to GSC , try to take what are the impressions and clicks for any particular keyword where you were ranking in 1st page in SERP? 

Its no surprise that in my 12 websites from March due to Covid there is big drop in Traffic and impressions.

Maybe, what I'm also thinking about, is that there is somehow a negative effect on the rankings because of the word 'meditation' is in the name of the domain. Maybe,.. but I don't think I can get an answer on this one ;)

domain name words is very minimal ranking factor but I don't think that all the websites that migrate have the same word in new one that they have in old one. But I have always seen the traffic properly shifting. 

In your case , I don't know about past but just today I checked and found that Google also canocalizing your old page to the new one which clearly tells that your site move is well recognized by SE. 

Have you checked , URL Removal/ Manual Section Message for new domain?

I am not aware of anything such as "Google Sandbox" in SEO. 

What I am aware of is set up redirects , allowing crawling of both versions, give proper canonical hreflang tag, internal linking and mobile tags if they are then wait for crawling . 

Also, even after crawling Google needs some time to evaluate the value of new content all the links processing etc and then only then ranking comes up .