found the problem, module https://www.opensource-socialnetwork.org/component/view/6608/image-editor changes the profile .gif to ,jpg
Disable this and it works

Well, all I see is:
The first images posted in the newsfeed 18 hours ago are JPGs like
https://onderwijssociaal.nl/post/photo/25/8e296a067a37563370ded05f5a3bf3ec.jpg

while the lastest post 16 hours ago is in fact a GIF
https://onderwijssociaal.nl/post/photo/27/02e74f10e0327ad868d138f2b4fdd6f0.jpg

Okay. Thats the problem. Upload.gif as profile avatar it becomes .jpg
Added in newsfeed it stays .gif

The gamer gif is working fine for me.
The image shown on https://onderwijssociaal.nl/u/beheerder
is not a gif but a jpg

indeed, more detail would be helpful
Okay, got this module running already.
My vps:

NVME-4G

RAM; 4 GB
CPU Cores; 4
Storage; 80 GB NVMe
Bandwidth; 20 TB / month
IP; 1 IPv4 + /64 IPv6

But it is the user avatar that does not animate.
newsfeed post works

resize it to 50x50 still no user avatar movement

See https://www.opensource-socialnetwork.org/component/view/3456/animated-gif-support

It's of minimal help to tell us the performance of your VPS
you'd better focus on an exact issue description in a new topic like 'animation gets lost after uploading'
That would save a lot of forth and back posts. ;)

update, when choosing the image, the thumb preview works. After posting image stand still

thought so

https://gifdb.com/images/high/gamer-498-x-498-gif-y805czpzyg0r4v7b.gif
and from the website
https://onderwijssociaal.nl/u/beheerder

gifs are accepted by default. just verified with a 498x498 image.
you may share your pic that doesn't work...