What OpenWRT are you using? If it's 21.02.x then you might need to manually downgrade the version of curl and libcurl4 (see this link: https://github.com/openwrt/packages/issues/19547#issuecomment-1271809668).
Although the fix has been committed already for 21.02 branch, somehow it wasn't included on some of the latest (as of this writing) archi release (ex: mipsel_24kc but is updated packages for curl and libcurl4 was included for mips_24kc) for 21.02.x. See my post here and here.