Can somone please help me in solving this issue. Im getting this Certificate verification failed er Sudo apt-get update

My organisation uses sophos firewall. Will 'SecurityAppliance_SSL_CA.pem' certificate help me solve this??

Hit:1 http://mirror.cse.iitk.ac.in/ubuntu bionic InRelease Hit:2 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:3 http://mirror.cse.iitk.ac.in/ubuntu bionic-updates InRelease
Hit:4 http://mirror.cse.iitk.ac.in/ubuntu bionic-backports InRelease
Hit:5 http://mirror.cse.iitk.ac.in/ubuntu bionic-security InRelease
Hit:6 http://archive.canonical.com/ubuntu bionic InRelease
Get:7 http://mirror.cse.iitk.ac.in/ubuntu bionic-proposed InRelease [242 kB]
Ign:8 https://desktop-download.mendeley.com/download/apt stable InRelease
Err:9 https://desktop-download.mendeley.com/download/apt stable Release Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 162.159.133.86 443] Reading package lists... Done E: The repository 'https://desktop-download.mendeley.com/download/apt stable Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.