If you are using Composer V1, it's worth noting that V1 packagist metadata is updated much less frequently since May '21, as mentioned here.
Reduced v1 metadata API update rate starting in May 2021
The update rate for new versions will be reduced from every-minute currently to once every 15 minutes. This means new releases will take a few minutes longer to be available for installation with Composer 1.x.
Restricted access to unused packages via the v1 metadata API starting in May 2021
This means new packages and old unused packages will only be visible to Composer 2 until someone installs them, at which point they will become visible to Composer 1 as well (within 24h as this process happens on a nightly basis).
If a newly uploaded package is not found, and you are using composer V1, your options are:
- take the slower updates into account and wait quite a bit longer
- upgrade to composer V2. V2 packagist metadata is updated much faster than V1 ever was.