Error: Please Verify Username and Password

Hello everybody,
i have the same problem like mentined here with suitecrm and 2 different websites. Before it is working. Then i reinstall the suitecrm from the ground as well the plugin.

Here was the same error message …
https://www.ads-software.com/support/topic/please-verify-your-suite-crm-credentials/

Thanks in advance
allnase