It seems to me that 50GB is the limit on a standard plan.
App Service limits
Standard; 50GB.
Premium; 500GB.
I suppose this leaves you with (at least) the following options.
- Upgrade your plan to Premium.
- See if Microsoft will raise your limit.
Azure subscription and service limits, quotas, and constraints
If you want to raise the limit or quota above the Default Limit, open
an online customer support request at no charge. The limits can't be
raised above the Maximum Limit...If there is no Maximum Limit column, then the resource doesn't have adjustable limits.
Find some other solution which removes the need to place data on your App Service. Such as a dedicated Azure storage mechanism, e.g. blobs, CDNs, Redis Cache, SQL, etc.
Look into App Service Environment.
App Service limits
The storage limit [of an App Service] is the total content size across
all apps in the same App Service plan. More storage options are
available in App Service Environment.
App Service Environment Storage
Each ASE is configured with 500 GB of storage. This space is used across all the apps in the ASE.