How to upgrade to Avast Moblie Security Pro?

[REDACTED]

"Next" button is not responding.

[bob3160]

Must be a language specific problem.
I had no problems in the English version.
I have passed this along to the developers.

[REDACTED]

@bob3160, thanks.

[Tereza V.]

Hi, are you in a country, which could be blocking Google Play Services (e.g. China)? Unfortunately, you cannot buy Pro from any of these countries.

[REDACTED]

Hello Tereza V., I do come from China Hong Kong SAR, but under the 1country 2 system policy, this should not be the cause.
Besides, my sony phone does not have this problem.
The device which is in trouble is HTC Nexus 9.

[Tereza V.]

Try to clear the Google Play and Google Play Services data (device Settings > Applications > Google Play > Clear data and Clear cache).

If it doesn't help, try this:
https://support.google.com/googleplay/answer/1267137?co=GENIE.Platform%3DAndroid&hl=en