Missing modules bcmath and gmp on security scan-- but these modules are present

Make sure that you’re activating the modules by creating php module configuration files in the right sub directory, e.g. /etc/php7/... Due to the fact that the directory can differ depending on the used distribution and you didn’t provide any information about your environment, I recommend to use the search function of this forum to find an answer or to ask aunt G. for help.

https://help.nextcloud.com/search?q=install%20php%20module