user7530: I compiled cardano-node 1.35.3 on another Ubuntu box and copied over, but it seems a library is missing.
cardano-node: error while loading shared libraries: libsecp256k1.so.0: cannot open shared object file: No such file or directory

What can I do to fix this?

user7355: Only took my second node for me to realize there is a line missing from the https://developers.cardano.org/docs/get-started/installing-cardano-node version.  The line below is missing from the docs but you can see it in sunapi386's answer
sudo ldconfig


user7530: You need to download, compile and install libsecp256k1:
git clone https://github.com/bitcoin-core/secp256k1
cd secp256k1
git checkout ac83be33
./autogen.sh
./configure --enable-module-schnorrsig --enable-experimental
make
make check
sudo make install
sudo ldconfig

Details https://www.coincashew.com/coins/overview-ada/guide-how-to-build-a-haskell-stakepool-node/part-i-installation/installing-ghc-and-cabal

7530: <p>I compiled cardano-node 1.35.3 on another Ubuntu box and copied over, but it seems a library is missing.</p>
<pre><code>cardano-node: error while loading shared libraries: libsecp256k1.so.0: cannot open shared object file: No such file or directory
</code></pre>
<p>What can I do to fix this?</p>
 7355: <p>Only took my second node for me to realize there is a line missing from the <a href="https://developers.cardano.org/docs/get-started/installing-cardano-node" rel="nofollow noreferrer">https://developers.cardano.org/docs/get-started/installing-cardano-node</a> version.  The line below is missing from the docs but you can see it in sunapi386's answer</p>
<pre><code>sudo ldconfig
</code></pre>
 7530: <p>You need to download, compile and install <code>libsecp256k1</code>:</p>
<pre><code>git clone https://github.com/bitcoin-core/secp256k1
cd secp256k1
git checkout ac83be33
./autogen.sh
./configure --enable-module-schnorrsig --enable-experimental
make
make check
sudo make install
sudo ldconfig
</code></pre>
<p>Details <a href="https://www.coincashew.com/coins/overview-ada/guide-how-to-build-a-haskell-stakepool-node/part-i-installation/installing-ghc-and-cabal" rel="nofollow noreferrer">https://www.coincashew.com/coins/overview-ada/guide-how-to-build-a-haskell-stakepool-node/part-i-installation/installing-ghc-and-cabal</a></p>
