Why won't my Samsung S4 Mini allow me to log-in (keeps telling me not valid)?

[AllanPatrick]

Help please, My Samsung S4 mini will not log-in keeps telling me not valid

My S4 mini will not, for example, log on to PayPal or any other login of mine

 

[B. Diddy]

Re: Help please, My Samsung S4 mini will not log-in keeps telling me not valid

Welcome to Android Central! Are you able to log into those sites or services on your computer browser? Are the apps telling you that the username is wrong, or the password? What's the exact error message you get?