Error at send email in main.neek

Why does this error appear when sending documents to email, if I already have my credentials?

Error at Send email in main.neek :Invalid login: 535-5.7.8 Username and Password not accepted. Learn more at 535 5.7.8 Check Gmail through other email platforms - Gmail Help h20-20020a05620a245400b006a693e46d5csm2457506qkn.11 - gsmtp. Please refer to Help Center to make sure the activity ‘Send email’ was set up correctly. If it doesn’t help, click this link to contact support.

Hi @Jose_Miguel_Almonte, sorry about this, please open a ticket with support on the support portal for further assistance and analysis on this.