Problem with updating AVG Anitviurs PRO for mobile Android

AVG Protection
1
I can not update my current application AVG Anitivirus PRO version 5.1.1.221227 originally installed in my currently bough new smartfone Alcatel Pixi 4 /6/ model 9001 with Andorid 6.0.1 into AVG Antivirus 2017 through Google Store. After many trials – when downloaded the newest version and the installation is started there is always error code 504  “the application can not be installed”.
 
All remaining applications are updated without any problem.
Would appreciate your help how to fix this issue.
 
Thanks and best regards,
Ewa
2

EWA, In future please refrain from carrying out multiple topic postings on the same subject! You won't obtain an answer to your query any faster!. Also please try to keep the whole conversation in one question/thread to speed up any resolution. Please see your other posting (https://support.avg.com/answers?id=906b0000000DcCZAA0).
AVG Guru