The instructions in Endevor for Endevor VS code extension:
Zowe CLI Secure Credential Store is not supported.
If you have SCS-enabled Endevor profiles, you need to recreate the profiles to successfully use them in Explorer for Endevor.
How to disable SCS-enabled Endevor profile in explorer for Endevor?
Release : 18.1
Component : EXPLORER FOR ENDEVOR v0.12.0
Right click SCS (Secure Credential Store) enabled Endevor profile in Explorer for Endevor, then click "Remove Profile"
New Endevor profile created in Endevor explorer does NOT use Zowe CLI secure credential store.
If SCS is installed in ZOWE CLI, ZOWE CLI Endevor profile update command will make Endevor profile SCS enabled, and can't be used for Endevor explorer.