Collabora error "please ensure the file type is supported and not corrupted and try again later"

hi everyone
i had nextcloud 15 with collabora code (not a docker, loolwsd 4.0.3)
and mkcert certificates.
i updated it a few days ago to nextcloud 18 and the newest loolwsd(4.2.0)
but it gives me the error in the title.
i tryed downloading it from the beginning and noticed that the error happens only after i install the certificates.
but it worked fine with them on nextcloud 15.

im currently on nc 18.0.0
collabora online 3.5.2
loolwsd 4.2.0
php 7.2

thanks in advanced