Error while processing the request! Unable to send message;Reason:530-5.5.1 Authentication Required. Learn more at 530 5.5.1 https://support.google.com/mail/answer/14257 b74sm6149143pfd.24 - gsmtp

Error while processing the request! Unable to send message;Reason:530-5.5.1 Authentication Required. Learn more at 530 5.5.1 https://support.google.com/mail/answer/14257 b74sm6149143pfd.24 - gsmtp

I keep receiving this error. I was informed that I was out of storage space in my account so I purchased two 5GB packages of space and that did not solve the problem (that feels like a rip off). I have gone through steps suggested to others with similar problems including signing in to email through zoho in email settings and that has not solved the problem. Please help me remedy this situation.